20 Most Recent Casio PRG-40T-7 Pathfinder Questions & Answers

It's probably the small spring which makes electrical contact between the watch aluminum back and the outer housing, presumably to provide an electrical ground connection to the outside triple sensor. I've attached a photo with the location indicated by the yellow circle and arrow. It goes in the little hole and will fall out if you're not careful.

open the backside.
probably the light switch contact at the six side of the watch (attached to the steel mainframe) may have contact with the electronic cirquit

here: Amazon com Energizer 395 399 Silver Oxide 5 Batteries SR927W SR927SW . I hope I have helped. Cheers

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

You can do it yourself. Unscrew watch caseback and undo the contact on top of battery. Read the writings on battery and buy exactly the same one. Do not mind manufacturers (Casio, Maxell, e.t.c.), just make sure the numbers are the same.
Some watch casebacks can be opened only if the watch band is removed, so, remove it if needed, just don't forget to memorize where every part and screw was fitted. Memorize how the battery is fitted and do not put the new one the other way around as this can damage your watch.
Actually there is nothing difficult - only you have to put everything back exactly the same way as it was. If your watch will be left without battery for more than 3 minutes, you will need to reset your watch after replacing a new battery, but it's easy if you've got users manual.
Good luck.

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If you look very closely you will see that one side of the clip goes nearly under the battery. the plastic there has what looks like a small hole near the metal. It is in fact a slot. use a straight pin inserting it in the slot and gently moving the clip away from the battery. There is bend tension on the clip and it should raise slightly when released. Then use a tweezer grab the battery.

use your tweezer to hook the clip back over th plastic after you insert 4 new batteries.

Have the same problem, Casio PRG-80L reads open. No hints about this in the manual. Nor did Votit's suggestion help. Note that although the watch is old there is clearly power left in the capacitor battery. Ended up accidently ito this mode when resetting the time. Assume the open mode is intended for service, but would just like to exit.

Follow this link:

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

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Click on my profile (escapement), then click on Tips and Tricks. There you will find link to all CASIO watch manuals.Rate me, please