I've removed the back of my casio db-36 watch, but I can't figure out how to remove the battery. The watch went blank last week.

The back has to come off in order to replace the battery. To loosen the stuck screw wet the tip of a cotton swap/Q-tip with WD40 (don't overdo it) and press it on the screw so that it seeps in between the screw and the back plate. Let it do its work for some 10 minutes and try to turn the screw. Use a watch maintenance screwdriver that fits well to prevent damaging the little screw.

Try a new battery. When water got in there it may have shorted the battery and drained it. It may work for a short time and then die. Also put the watch on you car dashboard in the sun to bake it instead of the oven unless you have an electric oven. For electric oven use a thermometer to get temp of 140 F then turn the oven off and put the watch in for an hour.

Open the back (4 screws). Careful with the rubber seal and spring inside. Use a pin to pry the battery clip away from the bottom of the battery. You need to pry the bottom out and up. When the clip releases, the battery is easy to remove/replace.

did u ever figure out how to get the retaining clip?

This may have a reset button inside the back , maybe marked a.c. if it does you need to short it with metal tweezers between the battery and the a.c. button.
hope this helps

The cover is removed by prying, - there should be a small notch on the back, just be careful!

1
ensure all three of the springs are present
the 2 at the top confirm that the case is closed the on at the bottom sends the sound signal.

2
ensure the metal casing on the back of the movement is not touching the back. and check the movement is correctly seated

Change battery

Use this page to download a copy of CASIO watch manuals in PDF format. To download a PDF file, enter the four-digit (or three-digit) module number marked on the back cover of your watch.

http://world.casio.com/wat/download/en/manual/


You will need a pdf reader on your pc, you will find all instructions in there.

If your databank is like mine (DB-35H), there is a TINY spring in a really unusual spot that you probably didn't notice that fell out. Laying the watch face down and with the back off, there is a little tiny hole in the back towards one of the corners. (sorry, already put my watch back together and didn't notice which corner.) There is a tiny (1/16" x 1/4") spring that sits upright in that hole. It must make a contact with the metal cover. I replaced my battery and when I did, a spring fell out. I looked all over the internet, then wrote Casio, who said they didn't have access to the information about where the spring went. (Doh!) I got a used DB-35H from my brother and was going to swap the innards when I noticed the spring on his. Put my spring back and it beeps! If you've lost the spring, don't know if you can fake it with tinfoil or not, but it really is a TINY spring. Good luck.