Replacing the battery in a Casio Databank 150 watch

[Update February, 2013: It's amazing how things have changed in a few short years. Everyone now uses their phone for all these functions.]

Like many self-respecting technology professionals, I wear a Casio Databank watch. In my case, it's the Databank 150. And when the battery conks out, you'd think that it was time to visit the local jeweler's or K-Mart service desk to get the battery replaced. You can do this, but only do it to watch the look of horror that appears when you hand them the Databank. "Oh, no, we can't service those. You need to send it in to the factory!"

Clearly they have been advised by legal personnel of the ramifications of losing the customer's data.

However, like many self-respecting technology professionals, I don't actually keep any information in my Databank. Those teeny keys are just too small to work with, and it doesn't sync with my computer's address book. What I find handy is the calculator function, which has proven useful on many occasions.

Anyway, you'd think that since the Databank is the choice of so many technology professionals, a quick web search would turn up instructions on how to change the battery. Nope. All we get is this review [2011 update: even that has been removed], with a URL that manages to exceed 256 characters. Note that this guy doesn't keep any information in his Databank either.

Disclaimer: following these instructions may render your watch useless. These instructions may be incorrect. I may be making them up as I go along. I will not be held responsible for you breaking your watch because you followed some instructions someone posted on the internet.

So on with the gory details. Toss aside your warranty, grab your jeweler's screwdriver, and unscrew the four tiny screws on the back. Lift the rear plate off gently so as not to disturb the waterproofing rubber gasket. Oops, too late. Well, do your best to stick it back in on reassembly. Remove the white plastic component protector gently, and you're looking at the battery.

The battery is held in place by a retainer that goes over the battery, heads down, and is kept in place by a plastic catch (see arrow). Unhook the metal retainer by pushing down and out on the retainer with your jeweler's screwdriver, and the retainer will pop loose from over the plastic catch. To clarify: you are unhooking the metal retainer from where the plastic catch is holding it in place. This is a delicate operation; don't push too hard or you'll ruin the retainer. Then remove the CR2016 battery and replace it with a new one.

Here's an ASCII diagram, side view, of the retainer and catch. The plastic catch is the "o".


Or it may just be an ASCII picture of a buffalo.

Reassemble and you're ready to go.

And even though I proudly wear a Casio Databank watch, it does not necessarily mean that I am interested in your watch. I'll say this as politely as I can: I've shared these instructions with you freely. I've posted as much as I know. Please do not contact me to ask questions about Databank watches. Thanks!


I wasted most of an hour trying to change the battery in my Databank 150 watch. Then I gave up and tried to find a new watch on the Internet...they don't seem to be available anymore. Then under "change casio battery" I found your instructions. (During that hour I lost one of the 3 springs...and found it in the CARPET!) 100% success thanks to your notes and those of the other folks on getting out the battery. I used a sharp pointed object to pull the metal retainer clip off the plastic tab.

I have changed the battery several times in my databank 150 over the years. Every time I have replaced the battery, it shows "OPEN" on the display. Before screwing on the stainless steel back, first install the plastic battery cover in the correct orientation (note the holes for the springs). While holding the plastic cover in place, push a metal straight pin into the very small hole in the upper right corner of the plastic cover until it bottoms. This will reset the watch (verify by looking at the display which should be normal now). Finally, screw on the stainless steel cover making sure the plastic cover remains in place.

Note, the straight pin is also the perfect tool for releasing the battery retainer.

Everytime I have taken one of these watches to the jeweler for battery replacement, the watch has been damaged beyond repair. And it doesn't make sense to send it out that can take a week for repair when (a) by this time the watch is useless (b) the store next door usually has one in stock. I've been wearing the Casio DB 150 since 1987 and love it. But when the BATT warning comes up on display - I purchase a new watch and swap the stretch band and discard the clunker. It's quicker, and painless. And just as easy on the budget not to mention the brain.

GREAT article. All that, and a sense of humor too!
I winged it many years ago, but by following the article, things worked better. No flying springs! And much cheaper than buying a new watch, @Anonymous Everytime. Really, do you even qualify as a geek if you can't replace a watch battery?

BTW, even w/o data, the countdown timer, alarm, and stopwatch are terrific assets in addition to the calculator's occasional usefulness. And you can set an alarm to remind yourself of an appointment - OK, that's data, but just a little. Very useful geek watch.

I realise this is a bit off-piste, but in case anyone has stumbled across this looking for a reason why the sound on their Casio Protek has packed up (as I have just done), the answer is down to the pesky little spring. I lost mine, but have made a "replacement" by making a staple out of a piece of 3 amp fuse wire and looping it between the two holes under the sensor. It works!

Hallo, leider kann ich niemand Englisch (Englisch verbessern). Ich habe ein billiges DBC 630 (Modul 1278) von 50 TELEMEMO acquiredly. Batteriewechsel nach dieser die Anzeige perfekt, auch die seitlichen Tasten funktioniert und welche für das Licht funktioniert. Ich kann Jedoch nicht ohne Einstellungen nicht durchführen Tastatur dort arbeitet. Ich kann nicht finden, einen Kontakt zwischen Tastatur und Modul. Kann jemand mir einen Rat geben es ist wirklich eine schöne Uhr, wie die ich benutzen würde.

Vielen Dank

Ich kann auch von der Innenseite zu machen und per E-Mail-Fotos, wenn es kann mein Problem lösen helfen.

Hello, here I send a parr to, written like above for my DBC 630 picture I have but operation instructions but I can alter nothing apart from the lateral push buttons. Meant I without the front buttons no attitudes of date and time carry out can that is this.
Who can help? Which feather produces a contact between buttons and module (1278)?

I've gone through 3 Casio Data Bank watches in the past 20 years. There's no other watch for me but the Telememo 30. It's so old that my first one was stainless steel with a stainless steel band. Now they're cheap black plastic. My last one's battery went dead today after 11 years. I could never figure out how to change the dead battery on my old Data Banks since installing a new battery always left the screen blank. From the hints on this page I exerimented and finally figured it out. After installing the new battery, short the back of the newly installed battery and the bottom of the hole marked "AC", with a suitably bent paper-clip for about 5 seconds. This will bring the watch screen back to life with the date January 1, 1985 (on my old watch at least). You'll lose all of your data, but at least you have your watch back. If your changing the battery before it completely fails (when the numbers are gray instead of black), write the data down before you change the battery. Now I can even bring my other two old Data Banks back to life! THANK YOU INTERNET!!!

"Thank you internet" indeed! But more specifically, thank you for the info. My watch died after changing the battery, and the paperclip trick worked quite well (though mine thinks it's 1990 - newer version and/or newer defaults, I suppose). It's a wonder that this trick isn't documented anywhere official, since this is the second time I've had it happen (and the first time I could fix it - the first "dead" one is long gone).

Now, if I could just find a better source for those easily-lost springs than another Telememo 30...

I lost the spring needed for the alarm to work on my EDB-110, and had great success with the tin foil idea. I just rolled a small piece of foil into a sharp, needle-like object a few millimeters longer than the original spring, with the idea that it would deform and make good contact with the piezo element on the inside of the cover when pressed against it. I might have been lucky, but it worked at the first attempt! Next time I change the battery, I expect to replace the piece of tinfoil as well.

Thank you for providing a Ph.D with instructions as to how to take their Casio Databank apart so they could change the battery. Went to Walmart, where I purchased the watch, and they refused to change the battery- saying they can't touch Casio watches, although the Casio manual says that either Casio or your dealer should change the battery ! In sum, will no longer buy any watch from Walmart if they can't change a lousy battery in the watches that they sell ! Thanks to your excellent photo and instructions, it took me all of 5 minutes to change out the battery. Am lost with out having a watch for it's much quicker to see what time it is via my watch than my cell phone.

All the Best,

After about 20 years my Citizen original calculator watch died, and even Citizen couldn't bring it back to life. Well, this is what I wore for 20 years, so what to do?

Well, the Casio DB 150 was the closest I could find, and I loved the "atomic clock" function. So, I've been wearing it for about the last 10 years when it went blank on me. Ok, so got the battery replaced, but what's with "open"? This blog helped.

As we all now know, everything is useless when it says "open." I tried the jumper option, but no-go. So, tried leaving the plastic cover off the back as one writer noted, and it worked! I only see two springs, so assume the third got lost, but even the light works again! (Must have stopped due to low battery. Even the atomic function seems to have power, too!)

So, thanks to all who wrote here. You helped save my watch!

How do you setup the atomic clock function? I have a Casio Databank 150 Illuminator but I can't see that option anywhere. Do some watches just not have it?

Decided to see if I could change the battery myself instead of taking it to a jeweler since it looked like a battery you could easily purchase. Followed instructions and everything worked beautifully! Thank you very much for posting the info, pic, and side diagram!

Worked like a charm!! Thanks so much!! Notes to others:

1. There may be some battery replacement instructions printed in like 4-point font on a sticker on the white plastic component protector. On my watch, the battery replacement was supposed to be followed by some vague "ALL CLEAR" command. I couldn't identify any such command; and it wasn't needed.

2. In a similar fashion, ignore certain instructions in the user's manual under "To Replace the Battery". Those instructions include the following after reinstalling the battery holder:
"Touch the AC contact and the battery (+) side with metallic tweezers." On my watch, not necessary!

I have a similar casio watch, I too had the OPEN symbol, the three springs had come out. The secret to getting them back in the correct holes is to look at the inside face of the back of the watch. Mine has the pietzo disk for the alarm and beep functions, and also a small brass coloured patch at the top edge. When the springs are placed in holes so 1 is in contact with the pietzo, and 2 are in contact with the small brass plate, it works! There are about 8 potential holes in the workings of my watch, and the 2 needed are actaly quite hard to see, but, figure out where the brass plate will be, and this is where to place the screws! hope this helps. Dave

Hi there and a big thank you!I've had a casio easy rec watch for a while now and the voice and alarm never worked ie no sound.The rest of the watch functioned well.I undid the back cover ,checked all the springs were in place and performed the AC function with a piece of thin wire.Now all functions work.Thanks a million for bothering to put this site together and in so doing saving many casio watches from the scrap heap.

THANKS SO MUCH!!! I have never replaced my battery before. You made it so simple! By the way, you can get the Data Bank 150 replacement wristbands on eBay for like $3-4.

Thanks for the great instructions - I had my watch open and couldn't get the battery out when I went to Google and found this page. That tip about the retaining clip was all I needed.

By the way, my Case voice memo watch (DBC-V50) has really low volume on voice playback. The beeps work fine, so I'm guessing that tiny spring is where it should be.

Any ideas?

Yes!!!! I won with your assistance and wisdom! This process was strait on. I'm particular and a little OCD. However, I am grateful for your help.

My Watch is a DataBank ABX-23 (Module 2358)

After replacing the battery and jumping the AC to the battery + the watch re-started Ok, but when I put the back cover in place the alarm was not working...

Reading all your post made me think about the contact between the back metal cover and the spring, I only had to spin the cover around 180º to allow the spring to contact a bare piece of the metal (there is kind of a plastic sticker on it that was getting in the way)

It all works fine again, Thanks again for your post :)

Worked fine. Saw that the screen said "Close" while working on it - but noticed that it goes away when the plastic protector is put back - which has a metal strip on the back so it can complete the circuit.

Did it with the smallest flat-head screwdriver I could find - initially had trouble with the catch but managed to get it with a pointy pair of scissors. Just pushed them in far enough to get in between the catch & move it outwards - looks like it might be some sort of circuitry board if I below this if I pushed the scissors too far & too hard. Initially I pulled out the entire internals when trying to pull on the metal flap without doing the catch - and after putting it back in - looks like my mode button doesn't work as its in a "pressed in" position. Should be easily fixed if I take the back off again & make sure the button isn't depressed. Oh well a bit more time than I thought - but the jeweller was on holiday, and at only £1 for 2 batteries from ebay (including postage) - far cheaper than what they would have charged me. (probably about £5?)

Using these instructions, I have posted a video on YouTube showing how to change the battery, if you're interested.

How-To Change Casio Databank 150 Watch Battery

Using the information at this site, I created a Youtube video of how to change the battery, in case you're interested...
Change Watch Battery

"Databank 150 community" !


Great instructions, and great follow up by others -- fantastic! All up and running. The one thing I had to piece together was the white plastic thing with instructions on it under the cover -- I had to orient that so the copper strip connected two tiny springs, and the other tiny springs stuck out through the little holes in the white plastic thing.

I love not being helpless. This was a lot of help

PS: I have module 1477.

Due to all the comments on these pages, managed to successfully change the battery on my Telememo 50 which I have had since 1985. The last time, I had a blank screen with my previous Databank watch and wasn't able to recover the watch. I could see why watch repair people seem to fear the casio databank watches, especially when I was in Europe and needed the battery changed (none of the stores I visited would touch it even if all they sold were watches!!!), but the hint here about AC was great since several attempts at simply changing the battery failed. I also saw "open" too on my last but successful attempt. Along with a jewler's screwdriver, you should have a tweezers with a pointed edge handy for opening the latch holding the battery. Like everyone else mentions, be careful with the springs or you may lose one.

Joe's Cat

Well, being a guy, I decided to change the battery myself on my DataBank 150. I have had it changed several times before at jewelry stores. After opening it I couldn't figure how to get the battery out, to went to Google and found this site.

Followed instructions and everything went well until I closed it up, and saw the OPEN message. I read all the comments on the OPEN message and still couldn't figure it out.

Then I noticed I was missing a spring, in the picture, the upper right gold one. I looked for about 30 minutes and couldn't find it, so I decided to experiment. I moved the right silver spring from the picture to the missing spot and closed it up. OPEN was gone!

Everything seems to work, except the sound is very faint. I can live without sound.

I used a dull sewing needle. It's smaller than a paper clip and easily fits in the small hole (dark area where the arrow is pointed) on the plastic catch. I just placed the point of the needle in the hole, pushed down and out, and the retainer came loose from the catch easily.

My very old Casio Telememo 30 stopped beeping after I changed the battery but now works great thanks to this site. Many thanks for saving my favorite and very old watch.

With this page (and with Jim Fox's comment of March 24, 2010, providing the "aha!" moment) I was able to resurrect my Telememo 30 -- which had sentimental value, being a gift from my late father -- from its apparent demise at the hands of a Walmart battery changer. Many thanks.

Replaced battery in my Casio Illuminator, F-105 "1572" just fine, thanks for your instructions.

But now that the battery is in, I am not seeing any numbers on the display. I know battery is in because the panel will light up when I press the light button (button A in the manual ) but the display is blank.

Pressing other buttons does not do anything.

I need this watch to work. Or do I give up and buy a new one?

Any advice?

My Telememo 30 was very similar to your 150 except it only had one spring. I had a small screwdriver, about 1/16" but it was to big to fit between the nibs on the catch. A pin worked a lot better to pry the metal tab out away from the battery to clear the plastic catch and release the battery. Thank you for your help. The instructions that came with my watch did not have any directions for replacing the battery.

Knowing what I had to do from the photo, I successfully used a sharp awl to release the battery clip. Also helpful was the tip to touch the contact at the BOTTOM of the AC hole. Watch is back in service!

Thanks -- just succeeded in replacing my Casio databank battery (without even losing my memos!) and couldn't have done it without the instructions as Casio doesn't tell you how to remove the battery retainer. The push pin trick was helpful in getting it off as was the instruction to push the retainer clasp towards the edge of the watch. Casio also says to touch the battery and Contact A with tweezers (or was it C?) but doesn't say where that is. Fortunately I either did it or it wasn't necessary.

This is one example of how the internet makes life easier: After reviewing the manuals, it was thanks to this page ONLY that I could make my Data Memory 300 and my Data Bank 80 beep again.

Just don't forget to place the coils in the correct holes; they have a tiny golden dot in the bottom and they are not too deep.

Add one more thanks from Mexico to your list. ;D

And God bless the internet!

This thread is superior. Helped me reanimate my EDB-610. Not that, alive, it's worth much more than it was dead. What a crummy successor to the old Databank line.

My theory on the wee springs: There's one silver one at 6 o'clock, that goes through a hole in the white plastic protector. Based on what others posted, that runs the beeper on the backplate. Perhaps in conjunction with the leaf spring at 3 o'clock?

Then there are the two brass springs, at 10 and 2ish on my model. Their purpose appears to be to complete a circuit through a brass strip on the white protector. In other words, they tell you that the case is open. It says "OPEN" above the time display. In case the fact that the watch has no back, and crap is falling out of it on the floor, didn't tip you off. Well, the crap doesn't fall out until you turn the watch over. To read where it says it's open and everything just fell out.

I had the devil of a time keeping those brass thingees in place, even after I figured out where the loose one went, and started working over a mirror so I could see the face without flipping the watch. Once, I had everything tamped down, ready to slide on the backplate. And my thumb shifted. I actually felt the spring split my hair in front, as it accelerated out of Earth's gravity for its rendezvous with destiny. Or Rama. I had to break open another old Casio for another spring.

I got so obsessed that I realized one end of the spring has a bit of wire sticking out, and you can actually slide that down a notch in the side of the hole, and give it a twist that seems to hold it in place.

One other thing. I was going nuts because I would jumpstart it with the tweezers -- actually, a paper clip -- and get all the springs in place, the white thing, that damn rubbery seal, and the back screwed down. And then, before my eyes, the display would fade gently away. WTF?

If that happens, give it time. Let it lie there, and think about what it's done. It will probably decide to come back. Although it may flash the "BATT" signal for a while, just to see if can wreak one more cry of rage and pain out of you. I guess the battery is upset and retires for a bit, after that part where you tried to short it out.

I tell you this so you won't do what I did, which was reopen and reclose the damn thing about 15 times when it faded out. It was only when it thought I had gone that it came back on. But I was just weeping, quietly -- I was sad that I would have to take a hammer and flatten it. Maybe it figured that out.

This seems like the right moment to mourn the passing of the old Databanks -- the 310, and its dumber cousin the 150. What I miss the most is the "schedule memo" function. I don't want just 5 alarms that beep at me. I want as many alarms as I need, that tell me WHY they're beeping! You can still get the 1500, which is like a 150 with bad make-up -- fluorescent buttons and a chrome job that comes off after a while and irritates your wrist when you sweat. I always came back to the old black plastic, and a black Speidel twist-o-flex band. The chronometrical equivalent of Tony, the P90-X Supernerd.

Hail and farewell.

My sincere thanks to the contributors on this thread.

What do I find important (on reflection)

First point: note how many springs/ copper thingees are sticking out.
Second point: the clasp holding down the battery
Third point: the AC

So (since this is anonymous), I open the back and read: REMOVE WHITE COVER. The only white cover is over the piezoelectric chrystal. So I remove it, more like scrape it off. Oops, nice one Casio - built-in obsolescence as a factor of Chinglish.

New battery, in place, then movement falls out of case. Get that back in one foul swoop and get a Noddy Badge.

Battery in place, AC with a gemclip, and then the flashing light that the new battery is flat. This went away after a while.

Then the springs. One? Two? Where's the copper thingy? doesn't have a PDF for my watch, or the other one, whether I enter the 3 digits in the box or the alphanumeric code.

Combining springs and and batteries, I'm left with NO sound and an OPEN CHECK message, and a spring in my sclera.

Maybe that's why Casio brought out the ten-year battery version.

Talking about "takes a licking, but just keeps on ticking"! Pretty good for a 4 year old blog post, huh?

I just changed the battery in my Casio Telememo, and couldn't have done it without this info.

Thanks for the comments re. those tiny, tiny springs also. Even though I knew that they were there (from the comments above), I had a hard time finding them after opening up the back. Luckily, none of them fell out


My watch recently showed "OP EN" in the area where the date was supposed to be. Upon reading your blog I tried the reset "AC" method. All is working fine now without even replacing the battery. Turns out there are three springs under the backing plate (back of watch). One is by itself and the other two are next to each other near the outer edge of the watch. The ones next to each other have a brass looking plate that's affixed to the backing plate when in place makes for a completed circuit. This little plate had somehow shifted out of position. It was fairly simple to move back into place and then the "AC" was shorted for two seconds and all is back to normal. I guess the glue holding this little part had gotten hot which allowed it to move out of place.

Hope this helps someone... Casio wanted $60-$150....

I've had this watch since 1997 since it was given to me as a gift by my now wife (nerds take note of the power of a Casio) and the battery only ran out this year (2011) probably partly because I didn't actually wear it very much.

I decided try to change the battery myself because I'm a bit of a skinflint and also like fiddling with things.

It's now back up and running but not before having the back off it seven or eight times over the past two days. I had terrible trouble with the tiny fiddly spring that fell out when I took off the white plastic back. But to cut a long story short, here are the steps I took to change the battery to get the thing working fully again. I couldn't have done it without the advice above, but there were still several things I had to figure out myself. If anyone is stuck with this specific model, I can e-mail you pictures of my dismantled Telememo 50 with crudely Photoshopped arrows or post them somewhere.

1. Unscrew the back
2. Poking through the white, inner casing will be three springs. The one in the top corner is the one that may give you trouble. Carefully lift off the back with a screwdriver. If the spring hops out, hang onto it and keep it for later.
3. Unhook the battery catch with a needle or jeweller's screwdriver. Put in the new battery and close the catch.
4. With a paperclip bent into a U, short the hole marked AC with the back of the battery for about five seconds. If the light on the watch does not go out, you've got the wrong hole, so try again.
5. If the spring is still in place, put back on the white plastc back and screw back on the metal back. The watch may still say BATT for a few minutes after changing the battery but this should go away.
6. If the spring has come out, do the following. Turn over the watch and the plastic back and lay them side by side. The face of the watch should be facing you, and the inside of the plastic back should be facing you. One end of the spring is splayed. Catch this end with a tweezers, put it into its hole in the plastic casing. Because it's splayed, it won't fall through. Lift the watch with one hand and the plastic casing with the other, keeping the watch facing you, and 'offer up' the plastic casing from behind and push them together in place. When you turn the watch over, the tiny spring should be sticking out of its hole, where you saw it when you took the watch apart. If you lose the spring, which I think is what allows the watch to beep, someone suggested trying some tin foil, which I think might work.
7. Screw back on the metal back, and viola, the watch SHOULD be working again. SHOULD be.

I also found this site and translated it with Google, but it has nothing about the spring and it's not in the picture, so maybe I've got the whole thing wrong after all. Even so, my watch is working - hurrah!

Used a needle to release the metal retainer from the plastic catch. Thanks!

Here's a solution to the missing spring problem. Take one of the springs you still have and carefully! stretch it to twice its length. Cut it in half. Scissors will cut them.

This is not for the ham-handed. Consider working over a large white sheet spread on a floor, since these Houdini-like springs will find every possible opportunity to spring, sprong, bounce, pop from tweezers, fall from anything etc. to try to disappear.

Put the watch together, have sounds but no dial light. Tracked this down to what I think is a tiny Hall-effect sensor on the circuit board. The light button bar (Databank 150)has a push-button under the right end, which pushes against a rubbery insert in the plastic circuit board holder. This rubbery insert is what holds the button in the up/off position. The other side of this button is a black pad that presses against a sort of "@" or "E" shaped metal "emblem" on the circuit board. I cleaned the circuit board side with an eraser.

Put it back together, the light works, but now there's no sounds. Tracked this down to one of the four tiny springs not seating properly. Despite being as careful as I can, I managed to lose it. Replaced it with a tiny bit of wire, taken from some braided copper wire, just the right length so it won't short out on the battery or retainer, and now everything works.

I am over 60, female, and not very technically adept. I used this website and the comments in order to successfully change the battery of a different, and smaller, Casio watch. It was tricky to get the thin metal strap hooked back over the new battery correctly, and I had done this myself successfully, but a tiny spring popped out during the operation and rendered the alarm function mute. Reading your comments helped me stay calm, understand the function of, and make a successful re-placement of, the tiny spring. Now everything works! Thanks, everyone!

Hello. I have an 18 years old watch, casio db 31 telememo 30 and after 10 years of not using it, I've decide to wear it again. So I've put a new battery, every thing seems normal but the sound is very "low" I can barely hear it. Can somebody tell me if the problem is the time of not using it, or should I try another battery?

While trying to figure out while I was getting the open and I suspect close message on my Databank 300 was that like everyone else found out that the little springs like to wander. I have changed the battery a few times over the years and never had a problem until now.

The fix was just call Casio parts and they have the springs for $1ea plus shipping got 6 springs just in case w/ shipping it was $10.95.

West Coast
PacParts, Inc.
15024 Staff Court, Gardena, CA 90248
Tel: 310-515-0207 1-800-421-5080

East Coast
American Perfit
1100 River Street, Ridgefield, NJ 07657
1-800-345-0537 or 201-941-0082 or 212-246-8292
Fax: 201-941-0083

On the Casio 1477 (probably other similar models) you can adjust the time keeping. Remove cover and plastic backing, you'll see a small round flat head of a slotted screw on the level below, turn minuscule turn clockwise to slow down, counter clockwise to speed up. Note that rubber gasket needs to stay in place and manufacturer degrades waterproofing after watch opening.

Thank you for this article. I have a Casio PAS-400B Pathfinder watch. The latch that holds
down the battery on my watch is almost the same, but a the jeweller's screwdriver that I have
is to wide to fit the small hole in the latch. I used the point of a safety pin (you can also
use a sewing needle) to nudge the latch outwards and it sprung open immediately.
Thank you again for this "how-to".

If your Casio does not keep time, the adjustment is left of the arrow in the picture above. Large hole with sloted screw in the layer below. Clockwise to slow, counter clockwise to speed up. Warning: barely turn. In Canada get your time from the CRTC at 10:00 am on CBC. Do not use any computer or cellular to check your exact time.