( Hundreds of people have signed this guestbook since July 1. 2003 )

Tell us what brought you here.
Tom Veik from Nebraska wrote on July 1. 2003, 22:03:
Since the search engines have picked up this page, I've been getting well targeted search hits nearly every day. There is definitely interest in this watch.

Stan Glaser from Yorba Linda, CA wrote on July 2. 2003, 20:07:
Actually, I was trying to find anything on the CFX-400, which I have (along with a CFX-200, also, with a VERY cracked crystal), but a google search on "scientific calculator watches" listed this site, so I popped on over to take a look.
My CFX-200 crystal was cracked accidentally years ago by our big golden retriever taking a playful bite on my wrist while we were playing.
My CFX-400 has gone through 3 "silver" cases and the "black" case that it is currently in is on its last leg -- I have exhausted all my local dealers of cases, and have tried everywhere in the US to find a new replacement case. The "black" case was purchased from a distributor in the midwest (it took me MONTHS to track them down), and it was the LAST one they had. I've run out of options -- and I LOVE THIS WATCH!!! I have just done some repair work with epoxy to fix the "hinge" area where the pins go into the small hole in the case, but I don't think it's going to hold very long :-( I'm so bummed...

Joe Boburka from Hawaii wrote on July 28. 2003, 22:21:
E-mail: jboburka at
I've been fascinated with Casio watches since the 1970s. I bought my first simple calculator watch (Texas Instruments) in 1980, I believe. Still have it. I've been watching the Casio scientific calculator watch phenomena for the past year, and it's amazing. Why on earth (with all the watches they have out there) don't they make a new scientific calculator watch? There is certainly a market!

Jim Millard from San Diego, CA, USA wrote on August 10. 2003, 21:35:
E-mail: jim at
Just resurected my CFX-200. It works just fine but I can not remember the setting sequence. Would much appriciate it if you could send the sequence via email.
Thank you.

Tom Veik from Nebraska wrote on August 11. 2003, 17:59:
I have received other requests for information from the manual so it is now included on the web page.

Dan Mitchell from Calgary, Canada wrote on August 12. 2003, 14:39:
I also have a CFX-200 which I have worn daily since it was new. It has been well used and is showing signs of age. There are a few minor scratches on the face and the silver finish has been worn off the buttons on the left side. The crystal is intact and there is no bleeding of the characters. All functions still work perfectly including the light and alarm, which I rely on regularly. I have been searching for another CFX-200 as a backup for the time when this one eventually quits. So far everything has been out of my price range. I found this site through Google.

Dick from Kentucky wrote on August 16. 2003, 23:45:
I'm in the market for a good very small scientific calculator to cheat on a standardized test. So far it looks like this model is it, and I might have to shell out $500 bukus on ebay to get it.
Then again, $500 buys a lot of other crap so maybe I'll just study harder, or better yet just cheat with a much cheaper normal calculator watch and sacrifice some functionality. Economics at work my friend..

Judith Anderson from Germany wrote on August 26. 2003, 03:47:
E-mail: Judith.Anderson at
Thanks so much for the on-line manual. I just bought one of these for my addicted-to-the-cfx series husband. Any idea where we can get replacement batteries?

Tom Veik from Nebraska wrote on August 26. 2003, 08:09:
The CFX-200 uses a BR-2020 battery. They are available at Digi-Key using their part number P185-ND.

Anselmo Almeida from Brasil wrote on October 13. 2003, 12:25:
E-mail: comfunde at
I have one since 1983, and it's still working. I've lost the manual and do not know how to set the date, and your page help me. Very useful page.

Mike M. from Tampa, FL wrote on October 13. 2003, 15:14:
Hey. I have owned a cfx-200 for close to 20 years. I bought it at a Service Merchandise store. I think it was $39 new. I've had to change the band, and I replaced the top row of buttons some 10 years ago, but it still works great. It is amazing how much these go for on Ebay. $450!!! I can't believe it.
Anyway, I like the site.
Mike M.

ruchan from turkey wrote on October 20. 2003, 11:03:
E-mail: rcak at
ý have the same watch working
but i need the glass

Geoff from USA wrote on November 6. 2003, 11:02:
E-mail: geoff at
Totally sorry that I ever sold mine... Amazing really that no one else has picked up the ball and built a replacement.

Steven - UK from England - UK wrote on November 14. 2003, 05:46:
I have just purchased and got a good condition
Casio CFX-200 it is in excellent condition for
20 years easily condition 9 out of 10.
I just need to replace the watch strap. It cost
me 320US dollars, plus I got hit for customes charges
of 46.50 UK Pounds (78.54 US Dollars).
Thus it cost me $398.54. I dont mind as to have a watch
like this in near mint condition is worth every penny.
Steven UK

Barrie from UK wrote on November 18. 2003, 10:18:
Gutted to do this - but my CFX-20 is up on eBay for sale right now (18/11/03):
with more info at:

Tony from US wrote on November 18. 2003, 21:04:
E-mail: tony at
Happy to see your page. I put up a similar one at I'm really hoping that CASIO will realize there is a market for a replacement for these marvels.

David Caswell from RI wrote on December 10. 2003, 08:59:
E-mail: dcaswell at
I too have a CFX-200 since 1985. I wear it often though not daily. Still works fine. Could not get an exact replacement battery but I use one with the same diameter and voltage slightly thinner. The #7 button popped out years ago but I made one from the aluminum head of a pop rivet gently pryed off the button panel face and super glued the new button onto the rubber mask. Have never had a problem since.

David Jacobs from USA wrote on December 12. 2003, 08:47:
E-mail: dbj44 at
I have a casio cfx 200 in need of repair. Can you suggest any person or organization that could repair this watch?

Lauro Tomio from Sao Paulo, Brasil wrote on December 15. 2003, 13:32:
E-mail: tomio at
For curiosity I was just trying to find out if somebody else have a 20 years-old Casio CFX-200, like mine.
I also have one of such watch, bought in New York in 1983. I worn it daily, directly, during 20 years, in quite different places (from very dry, as in Adelaide, Australia, to very hot and humid as in Recife, Brazil). It never required any repair. All the functions are still working
perfectly. The only problem is discoloration of the lateral buttons that are more frequently used in calculations.As I avoid using the alarm, the batteries usually last for
more than 2 years.
Thanks for the manual. May be I still have my one, but it
will be hard to locate it. As I see from the manual, the watch is not perfect, as the calendar is valid only till 2099!
Best regards,

William A. Thorman, Jr.--(Bill) from Cincinnati, Ohio USA wrote on December 16. 2003, 08:52:
E-mail: wthorman at
I had a CFX 200 which I literally "wore out." I sold it some years ago for $30 to a fellow in California. I have since realized I should have kept it especially with the display case and both manuals. When I saw a few Popping Up on Ebay at what I thought were confusingly high prices, I started doing some research. I have now purchased two of these great watches and I am always looking for more--at bargain prices, of course. I wish Casio would re-issue the watch. It took me a few years to stop trying to punch in figures on my Bulova Calendar watch daily wear timepiece..

Tom from So Cal wrote on December 16. 2003, 15:47:
I have owned both the CFX-200 and CFX-400 and always found them to be a great watch. The 200 is safely tucked away somewhere (it's safe because I can't find it) but the 400's (I have 2 - lucky me) are alive and well, thanks to a brilliant stroke of uncommon foresight. You see, in the early 90's I thought that Casio would come out with a third generation model, so I put the 400's away for safe keeping. Well, I'm still waiting on Casio, but the 400's never came out of the drawer until about a year ago when I checked on the internet and found that they had a definite following. New batteries and a reset and they worked like a charm. Both have been through re-builds, the last one in 1991 (it never got worn again). I still have the receipt on the last re-build: New case - $18.95; New band - $16.95; New battery - $5.00. Those were the days.
As to replacement cases, check for Telememo models of the same era. The cases may be interchangable with a transplant needed for the keypad. I believe that they were made in greater numbers and since the models are still being updated, older models in good condition should still be available for reasonable cost. I don't know what the CFX-400's are bringing since they never show up, but I've seen the CFX-200's bring $300-$400 in good to very good condition.

john from S.F. wrote on January 16. 2004, 01:55:
E-mail: scrumytum at
im proud to say ive owned my casio CFX-200 since 83. my grandparents bought it for me at the ripe age of eleven. it has been brought back from a long hibernation by my beloved wife who repaired the band after fourteen years of being broken. a long time to wait for the coolest watch EVER!!!! im thinking it will just last longer this way OHH YEA !! CALCULATING DADDY !!

Tom C. from Ohio wrote on January 23. 2004, 08:15:
I have a CFX-200 that I bought new in 9/86. I have both of the manuals (calculation examples + user's guide), the packaging materials (display case, etc.), and the original receipt as well. I came across it the other day while sorting through some of my archives and I was wondering if any others still exist. I'm surprised to see how valuable these have become. If only my wife would let me wear it (she has never liked it)...

Mike from Leeds, England wrote on January 26. 2004, 20:20:
I realised the other day that what I needed was a scientific calculator watch. Just like the CFX-20 I used to have at school in the early 80s. So I did a search of the online watch shops, gave it a damn good Googling and came up with... The watch I used to wear in the early 80s.
I know it has been said so many times, but it's incredible that nothing similar has been made for nearly 20 years! Fortunately my watch never got thrown away, just put in the back of a drawer and forgotten about, so I'm going to send off for a replacement strap (it's the resin model) and obtain a replacement battery. Fingers crossed! Ironically, the strap failure, and resultant failure of the local jeweller to be able to repair it, has resulted in a watch with relatively few scratches.
I would have loved a metal case to put the module in, but I think after 20 years that's hoping a bit much :o) The one I really coveted was the gold case version. I remember vividly seeing Mr. Rutan wearing one as he got out of the plane after doing the round-the-world record breaking flight!

Pablo from US, originally Argentina wrote on February 26. 2004, 18:11:
E-mail: lejarrag at
I bought two cfx-200's. One was ruined under heavy rain in Lubbock Texas. The other one works fine, except for the alarm. Do you have any idea whether this is a common event namely, the alarm not working? May it be that I am not using the right battery?

Tom Veik from Nebraska wrote on February 26. 2004, 20:06:
If you open the back of the watch, there should be two things that stick up, that need to contact the watch back. Both are necessary for proper operation of the beeper. One is a thin metal finger and the other is a spiral spring. Check to make sure they are both there and sticking up high enough to contact the watch back. Both I and another person who visited this site have had that spiral spring fall out.

Pablo from US, originally Argentina wrote on February 28. 2004, 09:19:
Thank you. I checked and the spiral spring is missing. I
regret now that I discarded my other watch instead of keeping it for parts. At the time I thought I could just buy another one.

Rick Nungester from Spokane, Washington wrote on March 7. 2004, 00:40:
Thanks for the manual online! I have watching eBay and see CFX-200s go for $150 to $300, about 1 per month. My brother and I (age 48) each got one decades ago. Lost or sold mine -- no memory of it. Mentioned it to my brother Bob, and he found and GAVE ME his! Thanks again.

Bruce from google search for casio cfx-200 wrote on March 9. 2004, 11:18:
Thanks for the online manual. I resurrected this old watch when my casio databank broke. Nice to see the following it has on the net!

Alan from Flint, Michigan wrote on March 14. 2004, 13:43:
E-mail: alang at
Resurrected my early 80's CFX-200 watch this morning. I couldn't figure out how to set the calendar and don't know where the instructions are. Thanks for posting them!

Jorgen from USA wrote on March 16. 2004, 23:27:
Hi my name is Jorgen, and I just purchased one of the CFX-200 watches from an Ebay auction, and it costed a little over $400, and the watch as it looks is in very good condition, although I am still waiting for it to arrive from the seller. The seller said the watch works fine, with exception of the light bulb. I use to have this same very watch, and I havn't been able to find it, so I decided to buy a used one. I looked for months for this watch, and I finally run into it head on, and this watch is very valuble, and will continue to become more valuble as time goes by.

Ron Dotson from California, USA wrote on April 4. 2004, 13:03:
Thanks for putting the Casio CFX-200 User Manual online. I still use my wristwatch but misplaced the manual.
-- Ron

Randall Logan from Maple Ridge, British Columbia wrote on April 16. 2004, 17:40:
E-mail: ScientificSolutions at
It's been more than 3 years since I tried a thorough search for new calculator watches! I just can't believe that Casio, or one of its competitors, has not created a new design!!
I simply must write them a letter.
Great web site!

dave hansen from Reno NV USA wrote on April 22. 2004, 01:56:
E-mail: dave at
I was looking for a manual for a CFX-20, still in excellent condition. Thanks for the information. Also have a CD-401 missing the 7 button.

Jay Peterson from Eden Prairie, Minnesota wrote on May 1. 2004, 14:11:
E-mail: jay_r_peterson at
My Casio CFX-200 is still going strong since I bought it in 1984. It is a little worse for wear. I had a Casio CFX-20 (plastic version) first. I have used parts from the plastic one to keep my 200 working. There is a Casio CFX-200 on ebay. The bid is up to $132. I don't know of a modern equivalent either.

John from Elm Grove WI wrote on May 6. 2004, 21:38:
E-mail: jkuenzle at
Just curious. I have a black CFX that needs a bit of repair. I did not knw there were CFX web sites around.
Maybe I can get mine working again.

pablo harguindey from Argentina wrote on June 24. 2004, 16:39:
E-mail: pablohar at
Man.. you bring tears to my eyes.. I had wish this watch since my childhood. Well .. please take care of it and don't never leave it near of me.. hahahah

Abe Mantell from Long Island, NY, USA wrote on June 25. 2004, 06:43:
E-mail: mantell at
Nice Watch (and well-taken care of)!!!!!!

Vince from Wisconsin USA wrote on July 26. 2004, 18:27:
I had a 200 from mid 80s to maybe 90, ear that held the
strap to the body broke. Tossed it thinking that I'd be
able to buy another sci calc watch for $5, progress
marches on you know.

I wouldn't pay $500 for a used one, but I'd pay $500 for a
new one. You'd think Casio could dust off the schematics
and build one for $250 and make a killing. With the
reputation of only selling them every 20 years, I'd buy
three or four and lock them away in a safe...

Casio, are you listening?

Eric de M Rodrigues from Brasil wrote on July 26. 2004, 22:41:
E-mail: ericggrilo at
Help...i have one casio cfx 200, but the display have a
problem...i need a new display. Please, Somebody help me?
I wait yours contact.

sam from california wrote on July 30. 2004, 13:53:
E-mail: sammadoo95126 at
hi....i bought this watch from dubai years ago, and i love it. It's all worn out and it's missing some buttons but nice to see some body else loves the same model!...bye

tim from london. u.k. wrote on July 30. 2004, 15:59:
E-mail: ts at
nice watch mate!
got one myself, not in as good nick as yours though!

Chris Watson from Texas wrote on August 8. 2004, 15:25:
E-mail: chrisf16 at
I just fixed the broken watch band on mine today. I had bought a new
calculator watch, but missed my scientific capability too badly. Mine
looks good as new also. I flew F-16s for about 15 years and this was my
watch. The trig and deg/min/sec conversions were indespensable for
mission planning.
Mine's the same, light bulb is out, but all buttons and keys work

BMLL from INTERNAUT wrote on October 20. 2004, 20:55:
E-mail: berniemarin at

Daniel J. Fuqua from Tulsa, OK, USA wrote on October 23. 2004, 13:27:
E-mail: losfuquas at
I loved my watch like that, back in the late 80's, until I busted teh crystal.

J. Soto from Caracas , Venezuela wrote on January 28. 2005, 20:11:
E-mail: multig at

My CFX-20 was in my closet during 15 years. I put the battery in and !!!!!!!is working great.
Thanks for the manual on your site due I lost it.
J. Soto

David Chu from Taiwan R.O.C. wrote on February 6. 2005, 11:52:
E-mail: gsm0931817888 at
I have two CFX-20 . they still can wark now . I like to buy 100pcs for new one! Can you halp me ?

Gregory V. Richardson from Anderson, Indiana, USA wrote on March 19. 2005, 16:47:
E-mail: omomom at
I still have my old CFX-200. It's a little worn, but functional (like me). I like to collect old calculators and slide rules of various sorts.

Bill Britton from San Jose, CA wrote on May 4. 2005, 19:27:
E-mail: beltona at
Does anybody have a line to someone in Casio's marketing dept? I/we should wise them up to the fact that there's considerable demand for a new Sci calc watch now that the '80's versions are giving up.

Ron Serafine from Escondido, CA, USA wrote on May 22. 2005, 04:45:
E-mail: rserafin at
I am still wearing my CFX-200. I have repaired it many times. It still works
well, but shows its age. I also have a CFX-20 with the crystal lost. Other than
that it still works fine. I use 2016 batteries w/a little piece of paper for a
shim. They work fine.
I bought both in about 1983 when working with radiation detection
equipment in nuclear power plants. They were very handy for figuring out 1/2
lives & detector sensitivities.

Terrence D. Reasor from USA wrote on July 6. 2005, 00:14:
E-mail: tdreasor at
I've purchased one of these when they first came out in 1983 and got a friend to get one then. It took me 10 years to wear out the first one and my friend swapped his for a newer databank model. I've now been wearing the second one since, well over 20 years with the CFX-200.
I will never know why Casio marketing doesn't try this model again, It should be even easier to make with todays technology, maybe better moisture resistance.

Tim G. Davis from Fort Worth, Texas wrote on July 25. 2005, 13:30:
I bought my CFX-200 new in '83 for $39.95. I still wear it though the bottom row of buttons don't work anymore. Makes it a challenge to set the date and time. I couldn't find BR-2020 batteries anywhere so I use a 2025 and hold it in there with a piece of paper against the back cover. It goes for about 4 years between batteries. I too would like to see Casio reissue this model, nothing compares with it. Thanks for this great site, which I found using Google.

Miguel LOLLETT from Venezuela wrote on August 1. 2005, 02:45:
E-mail: lollettp at
I Sell One

Ron Serafine from Escondido, CA, USA wrote on September 13. 2005, 01:43:
E-mail: rserafin at
Looking for crystals for my CFX-200 & CFX-20 working watches.

Ed Stanek from USA wrote on September 25. 2005, 11:26:
E-mail: Ejstanek at
I bought one of these watches new in the early 1980's. I have worn it everyday since. I have used it so much that my fingers have worn the chrome off the buttons on the sides and they now show as brass. It needs a new battery about once a year. About once every 5 years I have it cleaned or dirt can settle under the buttons and and they won't make good contact. I have spilled water on it several times. I have also worn it around the world and found that in extremely hot and humid climates it can temporarily lose its display. This happenned to me in Cancun, Bombay, New Orleans, and a couple of times in a steamy exercise room. It will right itself in about half an hour if put in an air conditiond room - the display comes back but it will have the old time and need to be set. A couple times it came back with jibberrish on the display. It needed to have the battery removed and reinserted to reset the display. My watchmaker says that over the years the seal on the case back has dried and allows too much humidity into the watch under extreme conditions - like 100% humidity and over 90 degrees temperature. It shuts itself down as a protection mechanism. But every button and every function still work perfectly under all other conditions.

Scott Mueller from Chicago area wrote on September 25. 2005, 20:06:
I bought a CFX-20 new back around '85, after going through a number of Texas Instruments calculator watches in the years before that. Unfortunately I found the user interface of the CFX-20/200 incredibly non-intuitive, for example I remember having to dig out the manual just to set the time and date! Plus it was too big and clunky for me. I went back to the TIs I had stored up before they were discontinued (still have one in fact). When the "new" CFX-40/400 was introduced, I jumped on it and never looked back. The user interface was vastly improved, I never even had to look at the manual to set the watch or use any of the functions. It was much thinner and lighter as well, and the batteries are not only easier to get but also last probably 3-4 times longer. Unfortunately all CFX-20/200 and CFX-40/400 models were discontinued in late '86, and knowing that no replacement was forthcoming, and that I'd never want another watch, I contacted Casio, signed up as a dealer, and bought *all* of the CFX-40s that remained in their entire inventory. Yep, all of 'em. Mine. A lifetime supply. In hindsight, I'm amazed I had the foresight, but I did. (g) Over the years I've worn (and destroyed!) many, sold a few here and there (nobody seemed interested in buying any in the late '80s and early '90s though), gave some away as gifts, but always intended on keeping enough to last the rest of my life. I even sold a few at my garage sales in the '80s and '90s (for as low as $25 believe it or not). Unfortunately those days are gone, and to my horror I am discovering that my inventory is dwindling to the point that I can no longer be cavalier if I intend to keep a few for myself. Of course everything has a price, so if you want a *brand new* CFX-40, then write me, I may be able to accommodate. I will apologize in advance for the price you will hear, but it is only because I'm now digging into my "personal stash", having broken, given away, or sold all of those I was originally willing to part with. The price only reflects my love for this incredible watch, and my desire to keep the few I have left for my personal use (I assure you that I do take *much* better care of them these days!). Don't blame me, blame Casio for not making them anymore, or any suitable replacement for that matter. As for me, I've worn no other watch except a CFX-40 for over 20 years now, and will be wearing one for at least another 20 more years, or until a suitable replacement shows up. I know that the calendar is good until the year 2076, and unless there is a miracle of science, that will be sufficient. (g) You remember the song: "In the year twenty - twenty-five, if man is still alive, if woman can survive,..." well, then there will be at least one man (me) still wearing a CFX-40. Scott - scottmueller (at) compuserve (dot) com.

James L Melby from Hamburg Michigan USA wrote on October 2. 2005, 20:41:
E-mail: jameslm at
Thanks for this site. I just got a cfx-200 at an estate sale and this manual will save time learning to use it. also I paid $10 for it, and had no idea it was worth more. Nice to know. I will be more careful with it now.

Guy Belanger from Trois-Rivieres (Quebec) wrote on October 9. 2005, 23:12:
E-mail: guyb_thinking at
I am a owner of one casio cfx-200.
I recieve it for a Christmast gift in
1983 and it still working the exe button
is gone and the beeper too but the rest
is running well. I don't use it anymore
because it's a metal case (not good for
an electrician)

Mark from Minneapolis, MN. USA wrote on October 19. 2005, 11:24:
I have two of the CFX-200's, both of them have display problems otherwise seem to work fine. One of them I did the same trick that you did, disconected the light to save the battery! Any idea where I could go for repairs? the last time I went to an "authorised Casio repair shop", they replaced the crystal and said they couldnt get the display. Charged me $130. and told me to get lost!

Ron Lutz from Texas - League City wrote on November 5. 2005, 22:35:
E-mail: ronald.lutz at
I used a Casio cfx-200 for years and when it died I replaced it with a Casio data bank. It finally died and I was able to buy a cfx-200 on ebay. Between the 2 I now have one good watch. I'm glad to have a working one again. I hope we can keep them alive.

Bill Rose from Goodview, VA wrote on November 12. 2005, 16:15:
E-mail: pwrose at
Wow! I was googling for instructions and hit your site.
Great to fins someone else that appreciates our vintage
calculator watches.
Many Thanx for the manual...I lost mine long ago.

Paul Sperry from US wrote on January 24. 2006, 06:52:
E-mail: paul.sperry at
I'm trying to reactivate my unique heirloom and have thus far failed to find how to reset the time. I greatly appreciate your manual photos, but could not find the actual instructions for setting the date. If you could help me, I'd very grateful. Thanks.

Paul Sperry from US wrote on January 24. 2006, 07:03:
E-mail: paul.sperry at
Disregard my previous message. I just found the time setting routine in an unexpected spot in the manual (the middle rather than the very beginning). Thanks much.

daniel from argentina wrote on March 2. 2006, 08:56:
E-mail: dgdipaolo at
Hi, I have a casio cfx 200 too since 1983, and it works perfectly. The Y2K does not exist for it. It's the best watch. Bye. Daniel

jay Evans from Texas wrote on March 27. 2006, 06:31:
bolught one at garage sale and looking for instruction manual. thanks

W. Hal Edwards from USA wrote on April 6. 2006, 10:21:
I still have my CFX 200 and have been trying to have it repaired for years. As a Surveyor, the thing was incomparably useful. The stresses of the job (sweat) proved its undoing. How the Hell in this day, no one makes such a device that worked so extraordinarily well is completely beyond me!

Steve Kitchens from u.s.a. wrote on May 9. 2006, 12:45:
E-mail: kitch48 at
WOW!!! what a cool watch! i had one as a kid back in the 80's, it was cool then and it is still cool now. although i now wear a Rolex Submariner, I still have a love for a vintage digital watch, especially trhe calcs. nice watch, enjoy! regards, steve

Gregg Hesling from Los Angeles, CA wrote on May 24. 2006, 17:03:
My father bought me a CFX-200 new in '83, and I've worn it ever since. My father's gone now so this has a lot of sentimental value, so I just bought a second one on eBay for daily wear. As a computer programmer, it was never subject to water, sweat, chemicals, etc. but I am about to open a bed and breakfast and the new watch won't have it so easy. By the way, here are some recent eBay prices for this watch (in working order): 8935480812 $252.28 300000262987 $172.50 8933992264 $223.50 6049540196 $177.55 Someone mentioned they bought their CFX-200 new in '83 for $39.95. Can anyone confirm this? This watch is so far advanced than anything before or since, and of such excellent quality and workmanship (as testified by the number of people still wearing one after 23 years!) that I can't believe it was so cheap.

Tom Veik from Nebraska wrote on May 24. 2006, 18:07:
Bought mine in 1983 for about $50 I think. Don't remember where I got it exactly, but it was some mail order outfit.

David Boyd from USA wrote on June 3. 2006, 08:13:
E-mail: boydda at
I had one of these (and a CFX-40 as well) in my teens and twenties. Alas, it finally died to a leaked LCD, and I no longer have it (or the CFX-40)... But I just paid a silly collector price to a guy in Brasil to get another, since this is one of the only two scientific calculator watches I am aware of, and I missed it! I remembered most of how to set it, excepting the method for switching to 24-hour time display. Thus I am here.

Paul from Canada wrote on June 11. 2006, 15:08:
E-mail: mrpaulchchan at
I bought the Casio CFX-200 for a little more than $25 since April 1986 and I have warned it everyday for the past 20 years. I am now using the CR2016 battery because lately it is hard to find the BR2020 battery. The CR2016 battery last about a year, will the BR2020 battery lasted me 3 years with a casual use of the calculator function. The watch looks and works like new. I found the BR2020 battery recently at The Source formerly Radio Shack at a Clearance of $1.99 Canadian. The link is: Greating from Canada...

RONNIE LEE from San Jose, CA wrote on July 19. 2006, 14:11:
E-mail: ronnielee at
I just found one the other day at a swap meet. I loved this watch back then and I am overjoyed to have one again. I don't have a manual however, so I am very thankful for your page. I wish you the very best. Take Care.

Rob from Netherlands wrote on August 17. 2006, 02:25:
Hi ! The casio cl and cfx watches are the best and nicest designs around! I put a threesome of watches online: Cheers !

Nick from Austin, Texas wrote on September 7. 2006, 07:25:
Hey, very useful to get the manual for these great watches. I have 2 of 'em. I, too, wear mine every day and love 'em! They recently ran out of batteries and I'm worried about finding more. Good luck with yours.

Kris Staller from St Paul TX wrote on October 9. 2006, 04:05:
E-mail: kdstaller at
I used to run a cleaning and repair service for the 20/200 and 40/400 series on the side and brought about 20 watches back to life. I might take on a few hard luck cases if my time permits. I have no spare parts, so if you have a cracked case or LCD, I'll need a spare one submitted in order to do the transplant. I've had the instructions for cleaning the watch up on my web site for several years now. If you attempt to tackle the job, make sure you do the work under a stereo microscope. Kris

Keith Radcliffe from Aberdeen, Scotland wrote on October 12. 2006, 14:04:
E-mail: keith.radcliffe at
Hi all, I have an interest in these classic Casio watches. I've never been lucky enough to come accross one of the scientific ones, but I have the CA-851, CA-901, CA951 and CD-401 databank. I wear these watches proudly every day and the amount of comments I get is amazing. Truly brilliant creations for the time, it's just a shame they dropped the metal casings and quality .....

Neil Rossi from Google wrote on October 24. 2006, 12:42:
I bought one of these back in the early 80's and wore it daily for almost 15 years until corrosion from sweat made the side buttons inoperable. It is a great mystery to me why no other company has produced one of these watches since then; maybe it's American science phobia. Does anyone know of a watch repair place that specializes in these watches? I'd love to get it working again.

Daryl from Wisconsin wrote on October 30. 2006, 08:09:
E-mail: dcrawmer at
I am wearing a Casio CFX-200 well. At one time I had a back up watch, but gave it to a friend whose CFX-200 crashed. I also wear a CS-231 basic calcualtor watch.

felix_77 from Germany wrote on November 16. 2006, 04:47:
Hi, after 2 years of search for a reasonably priced CFX-200 I finally was successful! It arrived yesterday in the mail and now I am a proud owner of a mint condition CFX-200. The previous owner had put a wrong battery in it (CR2025) that almost destroyed the battery clip holder, as it was too thick. Also the alarm wouldnt work with the CR2025 in the watch. Thanks to the advice on your page I replaced the battery with a CR2016, and now everything is perfect. What a great watch!

Sam Gonzalez from New York, NY wrote on November 27. 2006, 20:53:
E-mail: sam.gonzalez at
Hi there - I'm also the proud owner of a CFX-200 (which was my souvenier from a high school trip to London). I'm curious as to how you're doing with battery replacements these days. It seems that the DL2032 may work, but it's a smidge too thick and doesn't allow the battery clip to stay on, so I took it out. Also, I wasn't sure about the voltage and didn't want to fry my watch. A few questions: 1. What battery are you currently using? 3. Where do you find them? 2. Do you know the voltage of the BR-2020? Any assistance would be appreciated as I'd LOVE to bring my watch back to life after sitting in a drawer since the late 80s!! Thanks! sam

Tom Veik from Nebraska wrote on November 29. 2006, 06:27:
I'm still running with a BR2020 that I bought through Digi-Key, but they no longer carry them. For some reason, everyone seems to be dropping this battery size. It doesn't look like Panasonic makes them anymore. I just did an internet search and it looks like you can still get them from "Interstate Batteries". Here is the URL I never bought from these guys yet so not sure how good a source it is. If anyone does try them, let us know. Some people report having good success using 2016 size batteries, so that is an option too. The BR2020 is a 3 volt lithium battery. By the way, 2020 defines the size of the battery. The first 20 says that the battery is 20mm in diameter. The second 20 says that the battery is 2mm thick. So a 2016 would be 20mm in diameter and 1.6mm thick.

Jose A. miletti from usa wrote on December 13. 2006, 11:10:
It's a great watch. I misplaced the manual and stumbled upon this website looking for it.
Thanks for the valuable information.
J. Miletti

anthoja from germany wrote on December 26. 2006, 13:49:
now end of 2006 the watch works perfekt only i switch the year to 2005 (one year back)because the days are only then correct

Tom Veik from Nebraska wrote on December 26. 2006, 14:28:
You might be getting 1905 by mistake because the days for Dec 1905 are the same as the days for Dec 2006. When you enter the date, try entering it as 20061226 for Dec 26 2006.

anthoja from germany wrote on December 30. 2006, 06:12:
thank you for the help I have changed the date now described like tomes has date weekday is correct now gruss anthoja

Rocco from Florida, USA wrote on January 26. 2007, 10:44:
E-mail: rfmonaco at
Thanks for putting this manual online! Immensely appreciated!

Ameed Ansari from Islamabad, Pakistan wrote on March 8. 2007, 03:28:
E-mail: ameed.ansari at
I was just searching for this watch's manual and i bumped into this website... I was looking at the oldies of my Dad yesterday, when I came across his shining CFX200. Today is my first day with this watch on hand i.e. 8-March-2007. I was actually unaware of the uniqueness of this watch. This page has told me what its worth... Thank You Very Much! And Thanks for the manual... I was having trouble setting this watch!!!

Tom Veik from Nebraska wrote on April 25. 2007, 19:18:
My battery died a couple days ago so I bought a BR2020 battery online from Interstate Batteries. Got it in two days. The packaging says Interstate Batteries, but the battery itself is marked Panasonic. Cool, the watch works again!

David from Seattle wrote on June 11. 2007, 17:52:
I wore and used one of these every day for ten years before having it literally stolen off my wrist in Havana ten years ago. I recently found a replacement on eBay and came to this site for the manual. It's a terrific watch.

Finn from Norway wrote on June 15. 2007, 02:48:
I bought 1 CFX-200 (stainless) and 1 CFX-20 (black) in Japan sometime in the 80s. I recently found them going through my old stuff. Managed to replace the battery without help, but couldn't remember how to set the time and date, so thanks for putting up the manual. I wore only the CFX-20, but found that it was not sufficiently dustproof and waterproof for my workplace environment. The CFX-200 I bought mainly as a souvenir, so it's never been worn. I was worried that after 25 years the battery was leaking, but luckily - not.

Zach Fine from USA wrote on June 26. 2007, 06:28:
I was just looking for more info on my CFX-200... Took me forever to figure out how to program the time and date into it :)

Greg from Minneapolis / San Jose wrote on July 7. 2007, 12:51:
Worn almost continuously since 1983, though I rarely need the scientific functions anymore. No alarm, no light, lost the "1" button, cracked the crystal, and time-set button no longer works (urk), but for the moment it still rocks! Hopefully kdstaller's maintenance hints ( will take care of the latter problem, at least.

Jerry K from Las Vegas wrote on July 26. 2007, 09:34:
Need to see M\manual. Thanks for it.

Fausto Rodríguez from México City wrote on July 30. 2007, 19:59:
E-mail: fhri at
Great watch!!, mine is over 20 years and still working!!

Jim Horn from Google wrote on August 1. 2007, 12:18:
E-mail: jimhorn at
Good to find - I enjoyed my CFX-200 for years until the 8 key fell off. I replaced it with a DBC-671 and have missed the scientific functions. HP used to sell Epson printers with their own ROMs in them (the 82905 was an Epson MX-80) along with other such products from other vendors. They also don't make their own calculators anymore - Kinpo in China makes them for HP to sell (but HP designs them). So I've suggested to HP's calculator development head that they consider OEMing Casio calculator watches with scientific functions - but with HP's RPN operation. A win-win situation? Meanwhile my Palm Tungsten E tries to fill in... Many thanks for a good Web site!

Tom Veik from Nebraska wrote on August 1. 2007, 17:12:
An RPN scientific calculator watch? I'll buy one in a heartbeat. (Two thumbs up!)

Jim Baugh from Wisconsin wrote on August 9. 2007, 12:30:
E-mail: xlch62 at
I collect watches was given this watch in a large box of assorted watches. I have always liked large and/or multi-function watches. I was thrilled to find that, by just replacing the battery, the watch came to life. Finding your pages has allowed me to actually set and use the watch. Thanks you.

Ken Weaber from PA wrote on October 18. 2007, 20:16:
E-mail: weabeken at
I'd love to find another! I went through t least two of them (heavy perspiration), and now have to content myself with only four functions and 300 telephone numbers. It's not that bad, but sometimes I just want the odd trig function or logarithm.

Glen Robins from Brighton, England wrote on October 31. 2007, 05:49:
I've just bought one of these watches from Ebay at the staggeringly reasonable price of £61, and it has just turned up today. I had a CFX-20 as a kid in the 80s and the memories have just come flooding back. Even better than I remembered. A quick tip for anyone with a silent watch. To make the sound, the watch uses a tiny (and I mean TINY!) spring in the back which is all to easy to lose. I was sitting pondering how to find a replacement, when an idea struck me! Cracked open an old lightbulb, cut a few milimetres of the filament spring, stuck it in and hey presto, my watch chirps away as good as new!

Tom Veik from Nebraska wrote on October 31. 2007, 18:22:
Good tip Glen. Thanks.

mike from Fl wrote on November 9. 2007, 06:46:
Great old watch. Mine doesn't like the CR2016 batteries. The watch works, but if you hit the backlight, the watch resets... Bummer.

Adam Roman from chicago area wrote on November 19. 2007, 14:45:
E-mail: aroman at
Thanks for posting the Casio CFX-200 info. I still use mine and have questioned the actual battery size. I've been using a CR2016, so I'll get more life with the right battery. Thanks for letting us know. Regards, Adam Roman

Ron Norton from University of Maryland, College Park wrote on December 26. 2007, 16:08:
Thanks for posting the manual and for the tip about using a 2016 battery - seems to be working fine so far. My Dad loves his CFX-200 but hadn't been able to use it for quite a while before I came across your page.Ron

Glenda from Raleigh, NC wrote on December 27. 2007, 16:21:
My husband's father gave him a few of his older watches. I was trying to find the manual and your site made my task much easier. Thank you so much

theo vavouras from Thessaloniki, Greece [Hellas] wrote on January 1. 2008, 14:22:
E-mail: vavouras at
i owned a CFX-200 for a very long time at the 80' was a great watch-calculator.[thank you for the memories you woke up to me!]

Gary from AZ wrote on January 8. 2008, 20:22:
E-mail: quarx1 at
I also have a CFX-200 which I purchased in 1983 and just recently resurrected after 10-15 yrs non-use. I was looking for the instructions to set it. Thank you! The case is functional, but has some corrosion on the back around the outside. The buttons on the right side have lost most of the chrome. Do you know if the case and buttons be refinished?Have a great day ..... Gary

KEVIN from USA wrote on February 1. 2008, 16:35:

Ron Wright from Virginia wrote on March 11. 2008, 05:49:
E-mail: tronron at
I still own this very same watch. Bought it in NYC in 1986. It is missing 2 buttons and has been living in a dresser drawer you years. It was a great watch. If they still made scientific calculator watches, I would buy them.

JT from Belfair, Washington , USA wrote on March 17. 2008, 19:24:
I have always been looking for a scientific calculator watch to do X^Y functions but have never been able to find any. I didn't know these existed. With all our scientific breakthroughs, I would think an engineer wouild love a scientific watch at hsi fingertips. No market though I guess.

Ron Hellings from Bozeman MT wrote on March 19. 2008, 06:21:
E-mail: hellings at
Thanks for your site. My old CFX-200 went into my drawer when I bought my CFX-400 (whose calculator was much easier to use), but holes in the the plastic case on the CFX-400 eventually wore down and the pins came out, dropping my CFX-400 somewhere in the Gallatin River while I was fishing. I recently came across my old CFX-200, still a beautiful watch, in my drawer and found a battery for it. I am wearing it again now. But, anyway, the reason I am grateful for your site: I have lost the manual and could not remember how to set the date. Your on-line scan of the manual did the job. Please keep it up. Oh, and a note to Casio: come on guys, how much can it hurt you to put an old watch into production?

Dan Miller from Naperville, Il wrote on March 21. 2008, 19:19:
I bought one of these watches after having a calculator fail in the middle of a physics exam so that I'd never be without a scientific calculator again (and it did work). I never wore it much except for those classes. I happened to come across it recently in a box of old stuff and then came to your web site. I'm amazed that this technology (along with being able to go to the moon, when you think about it) disappeared more than 20 years ago!
I ordered a couple of batteries from apex and the watch is working fine (and I can set it thanks to your having posted the manual).
It's something of a shock that you can't buy anything like this watch any more - I've started wearing mine again, it's more amazing now than it was 25 years ago!

ved balkissoon from trinidad,west indies wrote on April 6. 2008, 18:55:
E-mail: vnighthawk at
I acquired the cfx-200 watch a couple of years ago,but, unfortunately,the retailers had misplaced the manual and was unable to assist me with the functions , since their resident "experts" were unable to get any of the functions working. I bought it and got it working without the aid of a manual.
I was still looking for a copy of the manual though,thank you for posting it.
The watch is fully functional, date,time,alarm, all calculator functions.
Like you, I'm not selling, but it is good to know that there are people out there who can still appreciate a good timepiece. It's a beautiful watch.

Steve M from US wrote on April 18. 2008, 09:42:
I've got one of those too. It hasn't had an operational battery in it for a good 8-10 years, though

Rick Marten from FL wrote on May 3. 2008, 11:27:
E-mail: rmarten at
Thanks for having the manual. I re-found my watch at the back of my bookcase (must have fallen years ago). Got a new battery. Still functions. But could not remember how to set the time.
Thanks to your manual, its fully operational, again.

testsujin28 from wrote on May 5. 2008, 22:01:
I wish I buy one back in the eighties

Kurt Calder from Galesburg, MI wrote on May 13. 2008, 05:20:
E-mail: binary512 at
I have worn the CASIO FX-200 watch since 1981 and it still works. I can't imagine wearing anything else, assuming there was something similar to replace it. The light is starting to go and whenever I use it, the watch will 'reset' and I have to set the date/time and some of the buttons are starting to stick. I wish everything I bought was of this quality. Sincerely, a very satisfied user.

Joe Ernest from Louisiana/Texas wrote on May 15. 2008, 14:04:
E-mail: jernest at
My Dad gave me one of these watches when I was at Texas A&M in the Environmental Engineering Ph.D. program in the late 1980's. I threw the watch into a drawer until my cool blue-face Seiko chronograph got modified by an automotive radiator fan. (Warning: Spinning blades...) On several occasions I forgot my HP41-CX and had to resort to that Casio for exams. With hands shaking from the previous night's Wild and Woolly Wednesdays at Double Daves, pressing the microbuttons was quite a challenge. Enzyme kinetics, air stripper tower design, biodegredation rate calcs., that little Casio did it all.

Brian from Cambridge,ma signed the guestbook on May 16. 2008, 04:36.

Cyril Munro from Antarctica wrote on June 7. 2008, 03:06:
I've had my CFX-200 since the early eighties and after all these years it still doesn't miss a beat. In fact, of the dozen or so watches I have owned over the last thirty years, the Casio is still the most accurate of all. It doesn't lose or gain much more than a minute per year! I still have it in pristine condition and I still keep it in my desk top drawer and use it regularly as a calculator if nothing else. They don't make 'em like that any more.

Alok kumar from india wrote on June 9. 2008, 07:34:
E-mail: at
i loved this watch.
i want to buy this,tell me the procedure and cost.

Carl from Virginia wrote on June 13. 2008, 22:24:
Great watch!! I still wear mine.

BriG from PacNW wrote on June 21. 2008, 13:42:
Had one in high school and college back in the late 80's. Band broke and I lost it. Luckily through the magic of the bay I was able to fine one as new-old stock out of Hong Kong a few years ago. Great watch.

Andy Brookefield from Germany, Hamburg wrote on July 9. 2008, 02:38:
I've got a Casio CFX-200 left over (including five CR 2016 which work perfectly as spare batteries for the next 10 years). Any Bargain?

Andres Juarez Valera from Mexico wrote on July 24. 2008, 19:20:
E-mail: ajv_73 at
I have this watch, I did get it in ebay, and it is new!!
Im very happy with my watch!!
Im from Mexico!!

martin cohen from los angeles wrote on August 2. 2008, 14:45:
E-mail: mjcohen at
My CFX-200 still works. I needed the manual to set the time.

morris from spain wrote on August 3. 2008, 02:45:
I have come across a CFX200 which I bought about 1980. I used it constantly in the early eighties in the medics, great for working. Have not used it since 1985 had a new battery installed with a 2016 all works perfectly now that I found the instruction mamual. GREAT.small crack in glass face

Alain CHAIZE from France (Paris) wrote on August 8. 2008, 10:14:
E-mail: alainclaude at
Hello !
I still use a Casio CFX-20 (the black version !) and it still works fine..even the bulb I did not disconnect !
I use 2016 batteries, the only problem with it is that when using the light, the display vanishes, which is a kind of paradox ! This is certainly due to the lack of amperage of this battery.
I did not know that this watch was getting value, until I made search on the internet to replace the battery !
I wish you the best !

Mike Nugent from Florida wrote on September 4. 2008, 14:38:
Takes me back to my nerd high school days. Great watch and brings back many memories. Thanks for the web page!

Lörincz Gyözö from Hungary wrote on September 12. 2008, 02:06:
Hello! I also had cfx-200 watch, but I sold it 10 years ago and unfortunately I don't manage to buy a new one.

Tony Owens from Australia wrote on October 1. 2008, 04:59:
E-mail: a.owens at
I bought my CFX200 at the the San Diego Flea Market when Chuck Silverstein
& I were visiting in 1985. He bought 2 & gave one to his dad Milt. Last week
I found the CFX200 when cleaning out a drawer. Naturally the battery was
dead. Took it to the local watch battery man. His response was "Ah, one of
these eh! Let's see if we can get a bit of a spark." Whatever he did, it works.
$14.50. I was happy. Not sure what battery. I stopped using it 10 years ago
when batteries were getting hard to come by.
Thanks for including the Manual. That'll help lots. I use the CFX200 watch
for its 3 memories. I include some cryptic codes for the basics of innovative
pedagogy. So when I get asked to teach a class without much preparation, I
use the codes. That way the "Force" is always with me. I assume the manual
will tell me how to access the memories May the force be with you too Mr
Veik! Cheers

steve dunn from yahoo wrote on October 11. 2008, 19:13:
I too have had a Casio scientific CFX-20 since 1983. It was working perfectly. Unfortunately it was stolen from my hotel room yesterday. I just can't understand why Casio never made a follow up to the model. It is the only full scientific calculator watch ever made. If anyone knows where I can get another one, please email me. Thanks.

Kathie from Valley Cottage, NY wrote on October 16. 2008, 14:18:
E-mail: ktiitsman at
I went online to try to find the manual. Your site was the first to come up. I received mine as a remembrance of my uncle and wore it for a couple of years with replacement battery CR 2016, but it didn't last long. I had lost the manual. Thank you for the manual and the link to the appropriate battery. It will be fun to remember my favorite uncle and wear the watch again.

Jim Millard from Idaho wrote on October 25. 2008, 13:32:
E-mail: jim at
I also have a CFX-200 still working I am using 2016 battery.

Alex from England wrote on November 9. 2008, 08:54:
E-mail: alex_002 at
Trying to find out how to set a Citron calculator watch
from the 1980s. Thought it might use the same chip as the
Casio, but this one only has four buttons plus the calculator keypad.

William C Gill Jr from Kingsport, TN, USA wrote on November 27. 2008, 07:21:
E-mail: wcgjr at
Thanks for having this site available. Your information makes it possible to acquire one of these without a manual and still be able to find out how it works.

Bruce from England wrote on December 16. 2008, 03:05:
Just starting to get into digitals. Came across a near perfect one at a camera fair, guy had a bunch of watches laid out near his cameras for sale. Seems he did not know much about the value of them as he sold it to me for £10. Wearing it now - very happy!

Zachary from USA wrote on December 24. 2008, 20:21:
As a teen, I drooled over ads for this watch in Scientific America. I never expected to own one. However, to my utter delight, I was bought one for a present. I took all my 10th grade chemistry tests with it. [Still was able to get an "A"] And over the years, on differing occasions, used the many "scientific" features in school.
It lasted 10 years. One by one the buttons failed towards the end. The brass case pitted. And we had to say goodbye.

Brian from Connecticut wrote on December 26. 2008, 15:58:
E-mail: Darktalos25 at
proud owner of a cfx-200, looking for the plastic version (cfx-20) if any one
has one available

George Wiegand from Cambridge, Maryland wrote on January 10. 2009, 14:47:
E-mail: gawie12 at
All I need for my watch is the button that goes to the INV function. Any ideas where I can get one?

Truls Ovrum from California wrote on January 22. 2009, 09:51:
E-mail: ovrum at
California via UK and Norway, now living in France.
Unpacking stuff we brought over from LA, I came across this watch, which I
haven't used for quite a while, and had forgotten about it.
Amazing to find this web site and with a manual! That is going to be very helpful
sinceI want to try to get it going again. I may have a problem getting a B 2020
battery here.

Kathie from Nyack, NY wrote on January 27. 2009, 08:08:
I am so grateful that you posted the manual. I received this watch as a memory gift of my uncle. The manual ended up in shreds, but I was able to finally get the right battery and now it's working like new. Many thanks. Kathie

Tom Veik from Nebraska wrote on January 27. 2007, 10:18:
I just noticed that the link to Interstate Batteries on the main page wasn't working anymore. So I just corrected that. The corrected link is

Bruce Cole from Oregon wrote on February 12. 2009, 02:25:
E-mail: bcole13825 at
I just purchased a CFX-200 at the local Goodwill store for $18.00! It works
perfectly. It must have a new battery because even the light works. This watch
looks new (not even one scratch). Lucky find!

Robinson Llano from Colombia wrote on February 16. 2009, 14:14:
E-mail: robinsonl at
Hola. Tengo este espectacular reloj desde el año 1984 de la serie en resina negra y 25 años después funciona muy bien incluso la lámpara interna. Me complace encontrar que aún existen otros usuarios de este reloj.

Chevallier from France wrote on February 27. 2009, 10:45:
I purchased today a "real" CFX-200 , it's a amazing watch!!!
J'ai acheté une vraie CFX-200 aujourd'hui, c'est une montre incroyable, un vrai bijoux , sans doute la montre la plus terrible que casio est jamais crée ( je suis un collectionneur de montre casio et je les connais pratiquement toute , j'ai aussi un faible pour la prt-1gp la montre gps :)
Vive la casio CFX-200 ( casio CFX-200 forever)
Chevallier from France

Daryl from Wisconsin wrote on April 14. 2009, 05:42:
I have one too. Still running. I used it every day when I worked in R&D

Philip Horsham from Penzance, Cornwall, UK wrote on April 17. 2009, 06:20:
E-mail: hph1641-pz2 at
I can't remember how many years ago I bought my CFX200, except that it was in Saudi Arabia (early 90's I think). The watch continues to give good service today, everything works but the LCD is developing a shadow in the bottom right corner. As a radio/electrnics engineer I found this watch a perfect little friend on field trips. Now I am retired the watch continues to be useful. If I need to make tha odd calculation without pencil and paper it's always at hand.
I was hoping that Casio still manufactured this watch, my search brought me here. It's such a shame the CFX200 is discontinued. Some complained it was too small but it was ideal for the field engineer who didn't always have his scientific calculator at hand. It's a pity Casio didn't upgrade it with GPS, I could have done with that many a time when on route to remote navaids sites in the desert.

steve from Connecticut, USA wrote on April 26. 2009, 09:28:
E-mail: sdunn57 at
This is by far the best watch ever made by Casio. It defies logic that they discontinued the whole line. I had my CFX-20 (plastic version) stolen while on vacation last year. Fortunately I was able to find a CFX-200 on Ebay. Without this watch I feel "naked" when I need to make a quick calculation. When all of these old watches die we will be left with no options unless Casio wakes up.

Bob Hayes from Northern Ontario, Canada signed the guestbook on May 30. 2009, 16:00.

Marty Bakken from Michigan wrote on June 15. 2009, 09:30:
E-mail: mbakken at
I had several CFX-20s and CFX-40s (black plastic cases and straps being the only difference between them and CFX-200s and 400s) back in the day. As I remember it, Casio first quit selling these great watches in the USA (high levels of innumeracy among the population - just not enough nerds...), and then worldwide about 18 months later - am I correct on that sequence? I've been lucky enough to acquire two CFX-20s on eBay at reasonable prices, and to learn about CSS Watch Repair in Salt Lake City - they fixed (overhauled) one of mine after the display wouldn't come back on after replacing a dead battery. By the way, CR2016 batteries have generally been working fine for me for years.
I would like to locate the financial calculator version of the CFX-40, which was the CBA10-1. In response to an inquiry of mine, CSS sent along a photocopy of a page from Casio's 1987 catalog showing the CBA-10-1: a twin of the CFX-40 with a ten digit display able to do compound interest, installment saving, as well as specific loan calculations - I'd like to give one to my eldest son, the bank vice-president.

Ricardo Santa from Burlington, Ontario wrote on June 18. 2009, 11:38:
E-mail: at
Thanks for posting the manual on your web site. I tought I had trown my CFX-20 away a long time ago but found in the basement the other day while doing some cleaning. Did some researched on the Internet and this guestbook inspired me to try to bring the watch back to life.
Installed a new battery, bought new buttons (got them brand new from a guy in Israel through eBay,), a new crystal and lid gasket from a dealer in NY and an original strap also from eBay. Threw in about $80 all in all and it now works like a charm: all the scientific functions, stopwatch, alarm, light, etc. Looks almost brand new. Very happy with the end result.
I wore to the office today for the first time in 25 years! Lots of fond memories from my days at the civil engineering school back in Colombia.

rajesh from india wrote on September 20. 2009, 21:12:
E-mail: rajeshwaravelu at
i am not able to adjest time and date pls refer me

Richard from USA wrote on October 17. 2009, 21:06:
E-mail: hwes at
I figure My CFX-200 has been inactive for 25+ years--I never replaced the
original battery. I got it out today, bought a battery at my local drugstore and
the thing works perfectly. All of it, light, beeper, display, everything. I was really
surprised. Cool to see all this interest.

Ralph Gretzbach from Germany wrote on October 18. 2009, 11:09:
E-mail: gretzbach.ralph at
Thanks for your article, I bought one CFX-200 as a student while visiting New York City in 1987. 'have the same problems with batteries...
Why does Casio not offer CWs with scientific functions anymore?
Greetings from Germany,

Matthew from UK wrote on October 20. 2009, 06:21:
E-mail: robopanther at
Hi, I recently bought a CFX-200 on eBay.
However the condition is quite worn. I'm looking to restore it to its former glory so if you have any spare parts for sale please contact me on the above email address. I am specifically looking for new face plates, side buttons, calculator buttons but I will consider buying any parts of this watch that you have for sale. Or indeed if you have a parts from a CD-401 (calculator or side buttons) for sale, I am also interested in those. Alternatively if you can put me in touch with a parts dealer (other than PacParts unless you have recently bought CFX parts from them with success) then I'd also love to hear from you.

cumhur from erbaa/Tokat/TÜRKÝYE wrote on October 25. 2009, 13:09:
E-mail: cum601969 at
casio cfx-200 kol saati arýyorum.Fiyatý nedir?

J. Fleenor from Midlothian, VA wrote on November 4. 2009, 06:37:
E-mail: b4xjjf at
I bought a CFX-20 watch in '83 at Service Merchandise for $23. As an engineer it was very useful to punch in calculations on the factory floor or conference rooms and have answers immediately. New watches seemed to be dropping into my lap as gifts etc, sending old faithful into a drawer after the last plastic band broke. Just a month ago I discovered it and purchased a new battery and band. Today I am wearing it proudly knowing new scientific watches do not exist and mine is worth a few bucks. I would love to find a CFX-200 to keep it company.

Adam from Germany wrote on November 10. 2009, 07:14:
I just managed to score two NOS CFX-400 watches last week!!!!
See pics here
Now I'm looking for a CFX-200 case to restore my old CFX-200 to its former glory. One of the side buttons has fallen off and 2 of the calculator buttons don't work but its still a great watch!
If someone has a non-working CFX-200/20 and would be willing to part with it, please contact me at godzillahercules AT yahoo D o t ca

ky4ham from google wrote on November 11. 2009, 19:35:
Thanks for the interstate battery info.Ordered 2 batteries arrived in 3 days!Just put new battery in my CFX-200.Works ok except the alarm no sound.Any suggestions?

Tom Veik from Nebraska wrote on November 11. 2009, 20:10:
ky4ham, If you open the back of the watch, there should be two things that stick up, that need to contact the watch back. Both are necessary for proper operation of the beeper. One is a thin metal finger and the other is a spiral spring. Check to make sure they are both there and sticking up high enough to contact the watch back. The spring fell out of my watch once and I had to replace it.

Scott O. from San Francisco, CA, U.S.A. wrote on November 12. 2009, 12:45:
E-mail: scott_94110 at
obtained CFX-200 at a yard sale, liked all the buttons. purchased a CR2032 battery at Radio Shack, and it works! your online manual will help me program it. Thanks for the forum.

Marcelo Carvalho de souza from Ilhéus-BA- Brasil wrote on November 25. 2009, 17:10:
E-mail: kauemarcelo at
não descobri como inserir data e dia da semana, podes me

Bob Linford from Starkville, Mississippi wrote on November 26. 2009, 08:23:
E-mail: boblin6 at
Thanks for the CFX-200 page. Great watches. Mine now resets when the divide button is pressed. I would really appreciate any ideas regarding how to repair it.
Thanks for the help!!

Baer Reid McKay from USA - Michigan wrote on December 19. 2009, 12:37:
E-mail: BaerReid at
Had the CFX 40. It was great, but it's been a number of years now since it died.
Was looking to get another since my last carpentry project could have used some trigonometry applied, and I missed the convenience.
Just amazing that they can't get another out to market. Even reissue the original. I know I would by one.

Jerry Goerz from Lexington, KY wrote on December 23. 2009, 18:38:
E-mail: JerryGoerz at
I'm still wearing my CFX-200 since it was new 26 years ago. I've opened it, cleaned parts, and replaced the battery many times. The side buttons are corroding, so I'm looking for replacement buttons, or maybe a junker to scavenge. Maybe replacement buttons could be made of a plastic like Teflon.

Kyle Vonderau from United States wrote on January 8. 2010, 19:37:
Received this as a gift from my uncle. Having trouble finding replacement batteries, but I am determined to get this working again!

Pat Picciano from Cleveland, Ohio, USA wrote on January 8. 2010, 22:50:
E-mail: patpicciano at
Hi - WOW!, great to see a webpage for this old wonderful watch - my dad bought 3 of the CFX-200 watches in the 80's for himself, my brother and me - I wore mine alot and used it quite a bit - so much so that the INV button in the upper-left of the watch fell out, but the button works if you press it with a toothpick. I will be getting batteries for these again to verify operation and selling all 3 of them. I was surprised to see some CFX-200's on ebay going for $50 and $80 or more! So keep an eye on ebay - I will be posting them if they work or not. My watch is missing the button, but I have the other 2 watches and they are still in "Like-New" condition. Thanks for the page and the chance to post here. Best of luck to all in the new year! Pat.

Kevin Watson from Hawaii wrote on January 10. 2010, 05:33:
E-mail: Avior at
Thanks, I'm on my second CFX200, and I also have a CFX20 around somewhere. Needed a quick look at the manual to refresh my memory. Thanks for posting it.... and I hope you don't mind I downloaded it.

Alberto Solano from Colombia wrote on January 11. 2010, 10:09:
Just looking my memories

Rick D from Georgia USA wrote on January 16. 2010, 20:52:
have a pair of these fine watches
purchased new way back when...

John from usa wrote on January 27. 2010, 13:41:
wow!!! thanks... just bout one for $55, but don't know if it works... an online estate sale... belonged to a NASA engineer.. the manual is going to be a big, big help, so thanks for your time putting it up!!!!!
i'll post you on how it goes...
thanks again & again & ag.... : )

Graystar_CAH from Albuquerque, NM wrote on January 30. 2010, 07:53:
I still have my CFX-200. I have to store it in a plastic bag with desiccant because the edges of the top right side of the display start to blacken if any humidity gets to it. I was able to order replacement keyboards and keyboard plates near the end of the watches life cycle to keep it working. It got heavy use but still looks new. I do hope a good replacement is made, if for no other reason than nostalgia.

Jim from Wisconsin wrote on February 7. 2010, 19:33:
I owned one of these great watches for about 10 years and it ended up broken when I took a fall on an ice patch. I sent it to a factory authorised repair service but they said it was not repairable. Bummer!

Robert D. Morris from California wrote on February 10. 2010, 16:23:
E-mail: morrisrd at
Just got my CSX-200 watch out of my jewelry box to use as I've misplaced my favorite watch. Needed to get instruction manual to set it up and found your web page. My casio CSX-200 is in almost mint condition as I've not used it for years. took the battery out of it and left it in my dresser. Is it true that the value of these watches has increased?? Just curious.

Robert D. Morris from California wrote on February 10. 2010, 16:37:
E-mail: morrisrd at
correction to my watch model no... it is CFX-200 but still in mint condition.

bill jacobs from usa wrote on February 11. 2010, 15:10:
E-mail: moperformance at

Reuti from Hessen / Germany wrote on March 1. 2010, 08:05:
E-mail: reuti at
On my CFX-20 the day of week is wrong since Jan. 1st 2010. Anyone else also facing this - is it the same on the CFX-200?

Tom Veik from Nebraska wrote on March 1. 2010, 15:06:
Are you sure the year is set to 2010 and not 1910? I'll bet that is the problem.

Wilson yano from Japan, Hamamatsu wrote on March 12. 2010, 14:55:
E-mail: Yano9001 at
Hi people, recently bought a CFX 200 through
Are in perfect condition, no scratches, perfect! I would post some pictures of it
here, but do
not know if it is possible.
Parabens pelo forum.
Wilson yano

Reuti from Hessen / Germany wrote on March 14. 2010, 15:22:
E-mail: reuti at
@Tom Veik: No, it's not 1910. It's easy visible: 1910 would show up as '10, but 2010 as 10 in the display (note the apostroph). And today on March 14th 2010 it's right again. I checked back, and it seems that for this watch February 28th and March 1st are both Mondays this year. But OTOH: February 1st 1910 was a Sunday on this watch, it should be a Tuesday. But January and March 1910 were right. Casio has no references any longer for this watch, how the dates are computed or whether they were pre-programmed for a fixed range.

Tom Veik from Nebraska wrote on March 14. 2010, 19:06:
Ah, you're right. 1900 dates are preceded with an apostrophe. I hadn't noticed that difference before. The CFX-200 doesn't seem to have the same date problems. I tried your examples and all were correct. Feb 28 shows Sunday, March 1 shows Monday, Feb 1 1910 shows Tuesday.

Robert Lirette from USA Wisconsin wrote on March 15. 2010, 15:02:
E-mail: blirette at
I have Casio CFX 200...havent worn it in many years. It is like new, what I am looking for is an instruction sheet. Do you know of anybody that has an instruction sheet, so I can reset everything on the watch.

Tom Veik from Nebraska wrote on March 15. 2010, 15:27:
There are links to all the instructions on the same page where you found the link to this guestbook. Down at the bottom of the page. Everything you ever wanted to know about the CFX-200 is there, except where to get a new one. :)

Kris Staller from Vail AZ wrote on March 15. 2010, 17:27:
E-mail: kdstaller at
Notice regarding watches that reset upon use of the side buttons:
The microcircuit in your Casio watch uses gold bondwires to connect the silicon microcircuit die to the circuit board. The bondpads on the die are made of aluminum. Over time and temperature exposure, the gold and aluminum fuse together and form an intermetallic compound. This process consumes aluminum from the bondpad and eventually leads to an open circuit condition. The average lifespan of a gold-aluminum bond is about 25 to 30 years before the open circuit conditions occur, some sooner when stored or worn in hotter climates. The open circuit condition is noticed when the side buttons on the watch are pressed. This warps the circuit board and places mechanical stress on the weak microcircuit bonds. If the bond is close to failure (a complete open circuit), the warpage momentarily opens up the circuit connection to the die. If it is the power or ground bond, the die will reset. The microcircuit on the CFX-20x/40x watch is covered with an epoxy dot which may slightly prolong the electrical connections, but it cannot be exposed and the bonds cannot be refurbished.
The bottom line is that watches exhibiting this condition cannot be repaired. Most of these watches are now over 25 years old and are on "borrowed time", so to speak. I would warn anyone about spending a large sum of money on the cfx watches, even those that are new-old-stock and never worn. Within the next five years, most of the CFX calculator watches will cease to function electrically with normal key press operation, and can only be used statically (as a timepiece only).
Kris Staller
Electronics Failure Analysis Engineer
Texas Instruments
Tucson AZ

Tom Veik from Nebraska wrote on March 15. 2010, 17:57:
Thanks for the info Kris. Mine is still working (knock on wood). Those darn intermetallics. At least we don't have to worry about tin whiskers.
Do you have any pull at TI? Can you talk them into making a fully functional replacement for the CFX-200. :)

Eric from Norway wrote on March 23. 2010, 13:36:
Cool watch. My uncle bought me a similar watch in 1984 I think when he visited
Tokyo. I adored it, and I still do. Sadly I do not know where it is now, probably
stored somwhere at home. I remember I was very carefully with it as the shiny
casing was easy to scratch. Maybe I will take a look after it and start wearing it
again, trhat is if I will get batteries. Remember it looked like out of the box
when I stored it away when a new watch arrived...

Bill VanOrden from Arizona wrote on April 23. 2010, 21:12:
Mine is still going!! Had to find out how to set the time as I changed the battery today, plan on using it to take my amateur radio Extra class exam tomorrow. K7BVO

Chris Holmes from United States wrote on May 24. 2010, 12:29:
My son was given one of these, but with a dead battery, and no manual. Thank
you very much for posting the info!

szalay lehel from Hungary wrote on June 27. 2010, 14:07:
Nekem is van ilyen tipusú órám.
Nagyon kedvelem.

ken from U.S.A. wrote on June 29. 2010, 16:11:
E-mail: kwnott1 at
had one batt died, put some where for safe keeping can not locate. See how safe it was!

Robin Datta from Fresno CA wrote on July 6. 2010, 23:07:
Here is another place for the battery:
Thank you!

Rocco from Florida, USA wrote on July 17. 2010, 16:27:
Looking for repair methods.
Why can't Casio make another Scientific Calculator Watch?
Thank you for this site !!!

David Fisher from Google search wrote on August 1. 2010, 08:23:
E-mail: Dfish6101 at
Found my cfx-200 and got it working for my high school reunion. Loved
it in the day, now I think it is a very cool watch that I will wear more

Bill Noyes from Kentucky wrote on August 5. 2010, 12:39:
E-mail: wnoyes55 at
I had one of these. I traveled to Japan, and they couldn't even fix it there. So sad.

John from Florida wrote on August 11. 2010, 07:39:
I've had this watch since 1985. Still have the original box with extra strap
links and the instructions. I just bought a CR 2020 battery at Wallgreens
for $4.81. I have the O ring problem with the buttons on the side so I just
use it for the time. The light is working. The calculator helped me in high
school and college. Thanks for sharing your experiences.

norm from omaha wrote on September 1. 2010, 09:18:
E-mail: nbemack at
Thanks for manual. It got me started. I've had watch since mid 80's. Have a problem with "D" key. When pressed get a lot of junk on screen and lose date and time. If anybody has got any suggestions, I would appreciate it. Have tried the jumper from gold post to battery, did not help.

Walter from U.S.A. wrote on September 8. 2010, 19:12:
I'v been looking for a new watch and I thought a scientific calculator watch would be cool. I had no idea they made so few. I've looked around and there's a website that sells a kit to make a scientific calculator watch. It is hope it helps.

Greg from USA wrote on September 23. 2010, 22:08:
E-mail: cgd62 at
happy to find a manual. just got mine. want a cfx-400 as

Gustavo from Argentina wrote on October 31. 2010, 20:13:
E-mail: geguzmanrios at
I have just bought this model. Unfortunately it is not
working. I hope I can bring it back to life.

vinny from florida wrote on November 20. 2010, 23:14:
E-mail: gsxr1000vinny at
I have a mint absoluty perfect condition look wise as well as working wise casio cfx-200 scientific calculator watch! I am the original owner was bought back in like the early 80's for me by parents! This watch is prestine i am looking to sell it for $400 neg you can reach me @

Mohammed from canada wrote on January 23. 2011, 06:41:
thank you for posting did a great job by posting the manual online, this really helps and it is a hard to find watch and its manual.

Andrew B from Brisbane Australia wrote on February 13. 2011, 21:42:
Thank you so much for posting the manual for this watch online. I recently dug out my cfx-200 that my Grandfather bought for me (when I was little kid) back in the mid 1980's. It hasn't worked for quite some time - needs a new battery - but having read the front page with the instructions on the battery type - will try to get the watch going. Once again, thanks for the information.

Tom Veik from Nebraska wrote on February 14. 2011, 19:01:
About a year ago my watch started malfunctioning. The date would spontaneously change to dates that were impossible. Months with more than 50 days. I would correct it and it would work okay for a few days, then it would do it again. It's been steadily getting worse, now with random resets, so I've had to retire it.

Carl from Virginia wrote on February 18. 2011, 23:47:
Condolences on retiring your watch. If you're looking for a replacement, I've seen them on ebay for around $300.

Tom Veik from Nebraska wrote on February 19. 2011, 06:49:
Thanks, but I suspect that Kris Staller is correct in his post above (March 15 2010), stating that these watches are likely to begin failing because of their age. I think it would be a mistake for anyone to spend a lot of money on one of these watches if you intend to use it.

Ron Lasky from Vermont wrote on March 8. 2011, 20:04:
E-mail: ronlasky at
I own two of these watches. Not sure if they work. Will be checking soon.

Maximilian from USA wrote on March 11. 2011, 05:12:
I loved my CFX-200 until it died halfway through college
(1992). Wore it along with a Casio Databank watch with a
double watch wristband I made myself. I moved up to PDAs
afterwards but still miss the immediacy of the CFX-200.

Jim Horn from USA: Columbia River Gorge (WA) wrote on March 16. 2011, 15:39:
E-mail: jimhorn at
My CFX-200 served well for about ten years until the "8" key fell out. I replaced it with DBC-61 which has the flat panel keyboard and is still running strong after about 20 years. Miss the scientific functions though!
Often wished HP would rebrand the CFX-200 (or 400) with a minor ROM change to make them into RPN scientific calculators. Minimal NRE or risk. But they got so burned with the HP-01 that they cancelled the HP-02 and -03 and probably won't ever sell a watch again. Sigh.

Tom from NJ wrote on April 30. 2011, 15:18:
Just found this in back of my drawer. Used it alot up to about 15 years ago. Just put bats in 'n works great.

Stephen Borchert from California wrote on May 17. 2011, 09:17:
E-mail: sjborch at
I just found mine in a box after years and ran out immediately
to a drugstore for a CR2016 battery and installed it. Casio
still makes the CA-53W which is water-resistant and has a lot
of the same "mojo" as this watch, even though it lacks the
scientific functions. Enjoy the CFX-200 while it lasts.

Mark from Sin City wrote on May 29. 2011, 12:53:
E-mail: pinguinxxx at
Googled Casio cfx200 and found your
excellent page on them!

pierre legault from Ottawa, Ontario, Canada wrote on June 20. 2011, 20:11:
E-mail: plegault1 at
I just found my CFX-200 after having lost it for 10 years. I am so happy. I had no idea users such as myself would still want this great watch. In the early 1980's, this watch turned heads and was wonder. I am not selling it after having it serviced. It works pefectly! Contact my if you anyone who may want one in great shape.

Carl Broady from USA wrote on June 23. 2011, 21:31:
Amazing. I just did a search on eBay and I see that there is a Casio CFX-200 for sale for $250.
I also did a search on Amazon. The Casio CFX-200 was not listed but there are were many other calculator watches available, some of them for as little as $19.00.
I will certainly be keeping my eye out for a reasonably priced Casio CFX-200 in good working condition.

VINNY from UNITED STATES wrote on June 26. 2011, 11:59:
E-mail: GSXR1000VINNY at AOL.COM

Ed S from USA wrote on July 11. 2011, 12:20:
thanks for access to manual. Decided to get watch out and use it after 10 years in storage. Still works fine but could not remember sequence for setting.

Matt from UK wrote on July 14. 2011, 04:19:
Just got another CFX-200, popped in a CR2020 and it works great. Excellent but not perfect condition for only $70, a steal really (especially with some of the prices I've seen for poor condition pieces on eBay).
When the light button is released, the display darkens momentarily. This also happens on my other CFX-200. I guess it's the gold micro bond-wires issue alluded to above.

Tom Thinesen from USA wrote on July 19. 2011, 19:33:
I have just listed a CFX-20 on eBay - so if you are in the market, here's you chance.

Mike from USA wrote on July 20. 2011, 17:45:
I had the chrome one. It eventually died. I think the display might have cracked. I replaced it with a black one that got funky and did the strange date thing like yours did. When I went to replace that one I discovered that Casio stopped making the scientific ones. All they had were the pathetic non-scientific ones and the "Data Banks".
I used to like the little "Space Invader" game that came with both Scientifics. Used to play it when I was otherwise occupied in the men's room at work.

Matt from UK wrote on July 25. 2011, 10:12:
The scientific Casios didn't come with a Space Invaders game. That was the CA-90 (

RainOfSteel from Utah, USA wrote on August 2. 2011, 20:16:
Watch purchased in 1986. Last battery died in 2007-2009. I haven't tried another since, so I don't know if my version would also be malfunctioning now. Y2K bug, maybe? Or physical malfunction?

Dr Colombes from U.S. wrote on August 4. 2011, 03:45:
E-mail: DrColombes at
Somewhere I have an old Casio CFX 200, hope I can find it.
Too bad Casio doesn't make them anymore. Cool, chic geek.

Daryl Crawmer from Wisconsin wrote on September 24. 2011, 18:11:
I have had two of these jewels. One as a backup. I gave my spare to a friend whose same watch had failed. Mine still work, but I could use an o-ring.

David Lewallen from google wrote on October 19. 2011, 16:51:
E-mail: davesgonedigital at
Hello Friends, I too have an original Casio CFX 200 in excellent working order, I purchased this watch in 1983 at service merchandise off buford hwy in atlanta ga. I have had to replace the band and have kept it on a plastic bag in a jewlery box over the years. I put a battery in it tonight and yep, still works great, only problem I see is the back light does not work, other than that the time set and keeps time, 20111019 year went in flawlessly and has been working all day with no problems, had to refer to manual to make sure all funtions on scintific calc still work correctly (and they do). I found this page earlier by accident and seen where this watch sold for quite a bit on money on 2003, and roughly 200-300 this year. I might be willing to part with this watch for a resonable offer @

john S Roberts from UK wrote on October 27. 2011, 13:19:
E-mail: J.S.Roberts at
I have had a CFX20 working daily since 1984 and apart from a little erratic operation of the odd button it works well. Over the years the time has gained by 1-2 sec per day, but I have not yet tried to adjust for trimmer capacitor.
I also have a CFX200 which I purchased from the US about 10 years ago. I have seen the display go to odd figures, but this has not happened now for several months.
I think these watches are unique and it is a real shame that Casio has never upgraded the design

Sheikhy from East Barnet wrote on November 2. 2011, 08:11:
What a ******** (pardon my swearing) beautiful watch! I had one of these when I was a teenager in the early 80's and wore the hell out of it! Shame about the battery issues.
I would still like to have one to look at and call MINE!!!

David from Illinois wrote on November 7. 2011, 04:27:
My CFX-200 continues to chug along. Had to replace a couple of buttons that came off and replaced the band as well. Many many years ago the watch quit working for some reason. So I put it in a drawer and forgot about it. After seeing the interest in this watch, I dug it out and put in a 2016 battery and it fired right up. Very strange but not complaining. Have replaced the battery a couple of times now and she continues to go.

Keith Dyas from Rosamond, CA USA wrote on November 7. 2011, 10:38:
E-mail: keith.dyas77 at

Steve G from Killen, Ala, USA wrote on December 15. 2011, 10:06:
E-mail: sgibson389 at
Stopped using this watch years ago because the batteries had to be orderd. Put a 2016 in it recently and it works fine. Found this site while looking for setting instructions. Never knew there would still be interest in this watch.
I have put the watch back on the Zuni Navaho watch band I had it on in the 80's and rotate wearing it along with other watches. Now, if only the eyes were as good as they were back then!
Thanks for the web site and the manual.

Gregory from Google wrote on February 21. 2012, 20:10:
E-mail: grjackso at
I know I have my manual in storage somewhere. It's really enjoyable to bring this old watch back out. Just reminds me of a simpler more enjoyable time.
Thank you for putting this manual online.
There where things that I just couldn't remember or guess how to perform.
Again Thanks,

John S. Roberts from Sheffield UK wrote on February 23. 2012, 03:18:
E-mail: J.S.Roberts at
I have a CFX20 and CFX200 and the 200 did show some of the reset problems you mentioned; however, it seemed to repair itself. I suppose it could be moisture and conductivity tracking. The CFX20 has been gaining 3sec per day and I was hoping to adjust the crystal frequency. The manual has no mention of this adjusmet, though there are two screw settings near the battery. If you have any info I would be interested.

JIMMY DURAN from MÉXICO wrote on March 10. 2012, 19:28:
E-mail: duyim at

Steve Rea from USA wrote on March 10. 2012, 21:28:
E-mail: srea1957 at
I just bought a CFX-200 from a fellow in Texas on eBay for $250.00 on a buy-it-now listing last week. In the pictures, it looked all scratched up, but, I've been wanting another one for over 25 years since my last one (bought new retail around $50.00 in 1984 or thereabouts) corroded and died from my sweat. I was astonished when the watch arrived and I saw it for the first time - it was perfect, including the original band, except for 2 scratches and 2 nicks on the front. The seller could have gotten twice as much for it on eBay for it's condition. But, it's mine now, and definitely NOT for sale! My 25-year search is over.
The display is weak and blanks out when I press the light button, so, I figure the battery is about gone. So, I just today ordered 3 Panasonic BR2020 batteries for $3.99 with Free shipping from seller "camfm" in GuangZhou, China, which should be here in 2-4 weeks (delivered by turtles, I guess!). I hope I have better luck with the batteries than I've had with other sellers from China - whom I've had a zero success rate with so far (3 transactions I had to get refunds on when they never arrived). I'm printing off the manual now to get ready to change the time to Daylight Savings Time tonight.

Gary Kendall from UK wrote on March 15. 2012, 03:12:
Thanks for the nostalgia. I suddenly remembered that I had one of these watches in my early teens - brought back from Hong Kong by a friend - so I did a web search. I don't think they ever sold in the UK.
I still have the watch - I only wore it for a few years before I became more style conscious. These days I prefer to wear a vintage Rolex.
I must try and get a battery for the watch to check that it still works. One day it may be worth more than some of my other watches!

amir from canada wrote on March 19. 2012, 20:38:
E-mail: alsudani at
thank you .

laederich from France wrote on April 10. 2012, 00:27:
E-mail: laederich at
Iam the proud owner of a CFX 200 and of a C 701.
I love them.
Do you know if there is a way to advust the contrast of the display?
I noticed they are some screw near the battery, that seem to be for adjusting something...

John Diehl from United States wrote on May 6. 2012, 10:49:
I needed a scientific calculator for a professional exam (not programmable) and
thought it would be gee-shiek to get a calculator watch. But to my surprise, no
one makes one that will do logs, exponents, trig functions, etc. anymore...and a
NOS Casio CSX-200 is $900 - yikes!

Vic Vidana from california USA wrote on May 13. 2012, 21:07:
E-mail: vidanav at
Hello, just found a CFX -200 in very good condition but needs battery(i hope)
and band (what fits). in $1.00 bin of old watches. all buttons are present and
display is clear as day. Must be my lucky day.

Terry Robinson from England wrote on May 21. 2012, 01:55:
E-mail: rotaryone at
Brilliant watch! Just replaced the battery, now can't remember how to set
the time and date. Must be the advancing years, and sad to know that this
watch is much smarter than I am now. Used it a great deal as a helicopter
maintenance test pilot for a major airline. Brilliant!! Just wish I was.

Bill Schmidt from Hewitt, NJ wrote on July 22. 2012, 13:27:
Own this watch, have it to this day. Its death happened when it took a swim in the lake. Miss its functionality to this day!! Really wish they would make a new style of it. If there are so many willing to pay 200 dollars for one when you could get a tablet for the same bucks just show how cool this watch really was!!

De Wagter from Belgium wrote on August 6. 2012, 15:45:
J'ai retrouvé aujourd'hui dans une boîte cette montre.
La pile était plate. C'était une pile Sony CR2032.
Je l'ai remplacée par une pile Panasonic CR2032 que j'avais sous la main.
Elle fonctionne. Mais comment la mettre à l'heure ? Sans manuel, j'ai deviné et trouvé comment la mettre à l'heure.
Mais comment mettre la date du jour ?
Merci pour ton manuel qui m'a permis d'y arriver.
Je pourrai aussi grace à lui utiliser ses 24 boutons.

Sergey Sivoklokov from Moscow, Russia wrote on August 28. 2012, 10:47:
I've got Casio CFX-20 (!) about 10 years ago from garbage.
Change the battery (got it from old motherboard, also from
garbage :) and it works! Even the light works. The only malfunction is alarm (perhaps piezo is dead)
Thanks a lot for providing this manual!

Sean from Gurnee IL wrote on August 28. 2012, 12:56:
Have had my CFX-200 since some time in the early 80's. Thing
is still in perfect shape although it did get retired from
daily use by 1990.

Adrian Ryan, 5B4AIY from Cyprus wrote on August 29. 2012, 09:43:
I was looking for a copy of the manual of the Casio CFX-200 calculator watch. I purshased mine in 1983 new in Canada, and it has been performing perfectly ever since, that's 254,000 hours! I use the CR-2016 battery, and it fits perfectly. It has never given me any trouble, and I calibrated it against an atomic standard and adjusted it, and its drift rate is a steady -0.765E-6 or about 66mSec/day. The display is perfect as is the case with no scratches or dings. I have not had any sticking buttons. As an engineer, I really appreciated having this calculator readily available, and, although a little tricky to operate with its tiny buttons, it has been a marvellous timepiece and accessory. Thanks for putting the manual on line, as mine is now very very tatty and worn.
Adrian Ryan

Keith Olsen from Princeton, BC Canada wrote on September 5. 2012, 10:16:
E-mail: epets1 at
Just found my old CFX-200 yesterday when I was cleaning out my storage locker. Thought I would see if it was still working. Having trouble putting in a new battery and was pleased to find your information on the internet.
Thanks for having the information available.

Paul from United Kingdom wrote on September 12. 2012, 13:03:
E-mail: jpwbamber at
Retrieved my old Casio CFX-200, read the manual and ordered a
battery. Tweeted this:-
'@jpwb Casio CFX-200 SciCal watch, been in a draw since ~ '86.
Just ordered BR2020 battery. Fan site manual. Works ?'
Thank you for your help.

Jerome from South Africa wrote on September 22. 2012, 08:19:
E-mail: rythmman007 at
Found your website, as I too have just found my Casio cfx-200 in near perfect condition. Haven't used it in over 20 years and it still works perfectly.
Can't believe what they worth!!! May consider selling it.


Richard Sauder from USA wrote on September 25. 2012, 11:25:
E-mail: hrs at
This was the best watch I ever had! Then, it began gaining speed until it was gaining a few minutes a day. Otherwise, it works fine.

Marcial from LA,California wrote on October 21. 2012, 17:37:
E-mail: lafieraherida at
i own one,since 1985 or 1986,still working.

Marcial from LA,California wrote on October 21. 2012, 17:56:
E-mail: lafieraherida at
i own one,since 1985 or 1986,still working.(casio cfx-200)

naveen from india signed the guestbook on October 24. 2012, 10:30.

Stewart from Earth wrote on December 1. 2012, 21:28:
E-mail: estewartw at
I've been trying to find a scientific calculator watch for a while now. A new one that I could buy somewhere. It's a shame nobody makes them anymore.

Dave Gerg from Kansas City wrote on January 10. 2013, 16:36:
Just picked one up at an estate sale. Stuck a CR2025 in just to see if it works - it seems to! Now, waiting for the CR1616 I just ordered from eBay. Paid more for the damned battery than I did the watch! :)

Michael Dinneen from New Zealand wrote on January 17. 2013, 01:19:
E-mail: m.j.dinneen at
Was just remember my old "nerd" watch and wanted to see manual/photo.

Tony Owens from Melbourne, Australia wrote on January 23. 2013, 04:16:
E-mail: dranthonyowens at
Picked up the CFX 200 in 1985 at San Diego Flea Market; the vendor was
supplementing his jewelers/watch business in downtown SD. Buddy Chuck
bought 2 both with plastic buttons (they wore out pretty quickly too. Mine is
still working today although I rested it for 15 years when mobile cell phones
came in.
Still have the original manual somewhere though currently mislaid (lost?). I
used the 3 memories when teaching. I kept cryptic notes as a format for
spicing up class action when teaching college classes. The contents used
were: Memory 1: Edward DeBono's 6 hats; M2 & M3 varied with topics taught.
Very useful! The best part was the look on the students faces as I consulted
my watch during class! I sometimes use the memories for shopping lists and
as hints for therapy protocols and lists of clients names.

anthoja from Germany wrote on January 27. 2013, 05:18:
E-mail: anthoja at
now end of 2013 the watch works perfect
what a wonderful watch

Julius from Austria wrote on March 3. 2013, 06:42:
E-mail: jul9999 at
I own one since the 1980s, rarely used and in very good condition.
Thanks for the useful and interesting site.

Charles from USA wrote on March 24. 2013, 12:57:
Thank You for the manual.

Nicholas from Pennsylvania wrote on March 26. 2013, 10:37:

Eric de Marques Rodrigues from Brasil wrote on March 29. 2013, 17:44:
E-mail: ericgrilo at
Ola amigo.
Agradeço por ter disponibilizado o manual do relógio. Eu tenho
um deles que acabou quebrando e agora consegui comprar outro
depois de 10 anos procurando.
Qualquer coisa, se quiser manter contato, tem meu e-mail.

lane woods from southern ohio wrote on May 20. 2013, 21:30:
E-mail: windwalker77_2000 at
I have both the cfx20 and
the cfx200 both are running. I am looking for the gasket for the back.

Mario from CLIFTON, NJ wrote on June 24. 2013, 16:51:
I had a CASIO CFX-200 back in 1983, which I used for many years.
Just got one from Ebay in excellent condition for $140.00
Luckily found this website and got the manual. Excellent website with lots of useful information about this hard to find timepiece.
Thanks for the info.

TomC from Detroit(FHills), Michigan wrote on June 26. 2013, 12:15:
E-mail: chrpkwcz at
Just replaced the battery in my CFX20 yesterday(it had been stored since about 86). Managed to fit a CR2032 in it!(?).
Still seems to work; will set the date/time tonight given your posted manual (haven't dug mine up yet!).
TomC Detroit, Michigan, USA

Johnny from Italy wrote on August 3. 2013, 10:30:
I still have my CFX-200 perfectly running, taken out of the bin where it was left for more than 25years. Just a new battery was needed to bring it back to life. It was a gift from my father in 1984, so it is reminding of him and of the great time I had just after I took my degree. And now that there is a great interest on vintage technology, I can't resist to put it on my wrist and trigger other's people curiosity.

Ron Wright from Virginia wrote on August 27. 2013, 21:44:
E-mail: tronron at
I bought mine in 1986. Used it until one of the buttons came off and it internally corroded. It lives in a drawer now. Best watch ever.

JayCop2 from Germany wrote on October 8. 2013, 14:05:
since a few days I am in the "Club" of CFX-200 owners!
I got 2 fully working pieces of them found on Ebay, one good for frequently wearing in leisure times and one in very good like new condition for my collection in showcase.
For me, CASIO Calculator-Watches are very fascinating because of the many useful functions, but also for plenty of buttons to play with :-)
At work I wear my CA-53W, at leisure time my CMD-40 Wrist Remote Controller and certainly my CFX-200!
I like the design of the buttons from those old CWs. Surely, the newer models are more waterproof, but the "Push-Feeling" of the old-school-buttons is much more better and handier then the flat-keypad in todays models.
In my opinion the CFX-200 from 1983 is defenitely the most durable, best to operate and mostly equipped (exept CFX 400) Calculator Watch of all times and I love it!
By searching I found out on WWW, that CASIO had produced the CFX-200 only 2 years in an edition of max. ca. 2 million pieces. The evidence for the pieces can be found on every watch because of the unique running number on the backside! I have checked a few dozens of them and found out, that every watch number startet only with 5 or 6 followed by five other numbers like 516922 or 698322.
Also there were originally delivered in 2 versions with different bracelets. The one you can open complete in two pieces. The other is fixed by a clasp that could be open and extend the bracelet to come over the palm of the hand, but will ever be hold it as one piece! Some interesting facts for collectors.
Okay, I have one tip for using the CFX-200. If you want to turn on/off the beep-tons from all buttons you have to go to the calculator mode and push the little flat steel button on the left side (second from above or "B" in the manual).
Thanx for this great site, the online manual, all Fans, Freaks or Nerds and keep the CFX-200 alive! Have a good time!

Zalmai from USA wrote on November 4. 2013, 08:00:
When I was a kid a friend of mine had this watch. I always wanted one but could not afford it. Two years ago, I found a lot of casio watches on ebay that had two of the calculator watch cfx-200 and so I bought them!
I like may watch!

Richard A. Dell from United States wrote on November 29. 2013, 14:13:
E-mail: rxd7 at
I have a CFX 200 since it was new. Need the manual
Richard Dell

Spencer from Canada wrote on December 11. 2013, 07:06:
Wearing mine today and still going strong. I don't wear it
daily because of its age and the fear of damaging it. I like
to use it when I am going for the retro-geek look.

James Mitchelson from Tampa, Florida wrote on January 25. 2014, 21:09:
E-mail: james at
I just recently found my old CFX-200. It still works (I put
in a CR2016) but I am missing 3 buttons. Too bad I can't
afford one to salvage the buttons from. Thank you for keeping
this page. Not much stuff left on the Internet.

Tiberiu from Romania wrote on January 27. 2014, 01:26:
Nice hommage to the CFX

Alan Dow from Kilmarnock, Scotland wrote on February 2. 2014, 14:34:
E-mail: veiks at
Hi there,
Thanks very much for the manual. Like many others here, I'm also very surprised by the current value of my humble Casio watch. I've had it since I was a teenager, i.e. since around 1984, I think. The decimal point button is missing and the strap needs a bit of work, but apart from that it appears to be working perfectly.
What brought me here is the information stating that a CR2016 battery will work. I can confirm that this is indeed correct, and it brought mine back to life after a "rest" of about 15 years! I am delighted, so thanks to all involved and best wishes to my fellow CFX-200 owners, hehe.
All the best,
Alan Dow

Bobby G from Thailand wrote on February 16. 2014, 19:14:
E-mail: drbobby at
Thank you very much - I found your page very useful as I have
lost my manual. Thanks again.

Andy from Los Angeles, CA wrote on August 8. 2014, 22:19:
I found this page via a Google search...
Amazing, the CFX-200 is still quite popular!
I am lucky to own a mint condition CFX-200, also a mint CA-851 of which I
am the original owner, a NOS C-80 and finally, a current-edition CA-53W
which is my weekend-beater since it is water resistant and inexpensive
($13 on Amazon). Yes, it is sad that calculator watches are outdated, now
that most cell phones and especially smart phones have calculators, even
scientific ones. Still, nerd-watches are super cool and I will always be
wearing mine proudly!

Josh from Murrieta CA wrote on July 13. 2015
Thank you very much for the CFX-200 manual! Sorry to read about your CFX-200 dying. Did you ever replace it?

- Josh

Phil Calendine from Ontario Ohio wrote on July 27. 2015:
In 1986 my parents bought me this watch, at my pleading. I used this watch in high school, breezing through Calculus and Geometry to the amazement of others (no "calculators allowed" one ever said anything about my watch. ) I have since repented for that unscrupulous use of this beautiful early tech watch.

I used it then through undergrad and half way through Medical School before the battery died. I put it on mothballs about 20 years ago and pulled it at the request of my 7 year old son. I got the CR2020 battery in 3 days from for about $8. I put the battery in (5 minute process). Your web sight was hugely helpful.

I did see that these things are going for $350-500 on! Wow.

Well, for now, my 7 year old is sporting a watch about as expensive as an Apple Watch. Too funny.

Phil Calendine, Ontario Ohio

David from --- wrote on September 9. 2015:

I have the cfx-200 in excellent condition that I bought in high school and
have not worn in many years. With the introduction of the Apple Watch, I
decided this style of clunky square with a silver band was popular again, so I
wanted to start wearing it once more. I just ordered the battery you
recommended on Interstate. The manual mentioned Opener B to pry open the back
at the notch. I see the notch, but I do not have Opener B and I cannot find it
to purchase online. Can I just use a flat screwdriver or knife blade? Where
can I get Opener B?

Tom Veik from Nebraska wrote on September 9. 2015:
I just use a small screwdriver to open mine. A small knife blade will work also. The back just pops off. Just be a little careful when you open it. There is a small spring in there that could fall out if you turn the watch over with the back off.

Markus from Germany wrote on September 20. 2015:
Hello Mr. Veik! My CFX-200 still working fine, i hope you find a good one again!
I am still watching CFX-200 auctions on ebay, the prices for them are going higher and higher. On this auctions i found out, that there was/is a second guidebook, that originally delivered with this watch. Beside the grey/green "Module 197-Users Guide/Manual", which we all know very good thanx to you :-) there is a second white guidebook called "Module 197-Calculation Examples", which probably gives more important advices to scientific calculating operations or input formulas to exploit the full potential of this great watch! (Some examples can found in the "Users Guide/Manual", but not many)

So, please can you help to find this "Module 197-Calculation Examples"-Guide?
Or does anybody, who luckily own it, could scan it to share it?
That where amazing! Thanx for your help!

Tom Veik from Nebraska wrote on September 20. 2015:
Interesting, I haven't heard anything about a second guidebook with calculation examples. If you find it, send me a copy and I'll post it here. I'll poke around a little too and see what I can find.

Markus from Germany wrote on September 20. 2015:
Hi, thank you for your quick response!!!
Maybe you can find some facts about it.
I send you 3 pictures with this mail where you can see, what i mean. So please dont be afraid, i swear its not spam or something else.
On this pictures you will find the CFX-200 with both guides! I found ithem on Ebay.

Thanks again!
Best regards from Markus

Picture link 1    Picture link 2    Picture link 3

Tom Veik from Nebraska wrote on September 20. 2015:
Thanks Markus. I'm quite certain I never got the second Calculation Examples manual with my watch. I wonder why. I would still have it if I received one.

Joe Philipps from Cheektowaga, NY, US. wrote on December 24. 2015:
I got mine in the early '80s. I used to forget I had it on, and play
racquetball with it. I thought it was remarkable just how tough the
crystal is.

I do remember losing the battery clip sort of soon. My backlight
burned out/filament broke (not sure which). I also have no idea what
happened to the square seal for the back. It's still quite
functional, although a few times I have disassembled it and cleaned it
with alcohol and a swab. The side buttons as you notice tend to
stick, but not all the way on/in for me. The display module
unfortunately is somewhat mottled, I think from the salt from sweat,
but still quite legible. It gains about a second and a half per day,
although I could have sworn at one time I tweaked one of the screws
inside to regulate its speed successfully, but no more. (seems the
bigger one is display "contrast" and I thought the smaller one was
speed fine adjust.)

2016 cells work OK, I've also been using the 2032 (since they're used
for computers' real time clock and configuration storage) basically
without a problem. The back does close with one of those in there,
plus a small sheet of paper for insulation. If I recall correctly, it
only needs a new cell maybe once every other year, which is remarkable
because I keep the hourly chime on.

Tom Veik from Nebraska wrote on December 25. 2015:
I'm surprised I didn't loose my battery clip. That's just the kind of thing that can easily fling off and get lost. I never did try messing with those little screws. The time accuracy on my watch was pretty good. Makes sense that one would be for adjusting LCD contrast.

Craig from California wrote on June 25. 2016:
Hi there,

Thanks for the site and instruction book! I bought my casio CFX-200 back around 1983 while a freshman in high school. I think I only wore it a year or two before taking it off over concerns about its lack of water resistance. I didn't want to ruin it.

For some reason I thought I had lost it or it was destroyed, but I just found it in a storage box. Funny, my watch had a 2025 battery in it and I don't remember changing it way back when. But I put in a fresh one and its working great, all buttons and light as well. I too had been watching the value of these things going up over the years, so now I'm faced with the dilemma: hold onto it or cash in? Well, no need to decide right away....

Todd from St. Charles, MO wrote on November 7. 2016:
I bought mine with a bunch of engineers at McDonnell Douglas in 1983.
It has been packed away since I met my now wife of 22 years. She was not a fan of it.
She made me give up my Jams (shorts) and striped white sox along with my cfx-200.
One of my sons saw it and thought it was the coolest watch he has ever seen.
So I put a 2016 in it, set the time and it works like a champ.
Note: The apple does not fall far from the tree.

Mario wrote on January 10. 2017:
Hi Tom,

Bought a CFX-200 Casio watch about a year ago for $120 on Ebay.

It is in perfect condition, i love it, however the last time i had to change the battery (SONY CR 2016) it took me a while to attach the retaining metal clip. I love this watch so much that i do not want to mess anything up. Do you know the correct way to position the retaining metal clip in place?

Thanks a million,


Tom Veik from Nebraska wrote on January 10. 2017:
Hi Mario

Nice find on Ebay! About the battery clip, not really. I just wrestled with it until I got it to go. The odd thing is that the manual talks about removing screws(s) from the battery holder. Mine didn't have any screws. It was just a clip.

Unfortunately, mine doesn't work anymore. It gave me quite a few years of good service though.