Russ' Do It Yourself Home Workshop

Finding Fixes to Just About Anything and Everything

Replacing the Battery on Your Casio Calculator Watch and Resetting the Watch

Posted by Russell Wright on June 7, 2009

Okay, so I’m a geek and I wear a calculator watch (most of the time). I’ve been sporting the Casio CA53W-1 since about 1980. I’ve had several.

Replacing the battery is not good for over 40 eyes. You definitely need some magnification! If your remove the 4 screws from the back you have a tiny o-ring that seals around the back and a CR2016 battery that is held in place with a clip. There is also has an insulator attached to the clip.

Push down on the battery to slightly flex the clip and use a small jeweler’s screwdriver to carefully detach the clip side that is located toward the keyboard. Once you hook it, it shouldn’t take much. Then, carefully remove the clip and insulator.

Place a new battery in the compartment, + side up, and hook the clip/insulator to the top hook and then press down to flatten the clip. Use your small screwdriver to carefully assist with attaching the bottom part of the clip. Don’t rip up the insulator!

After installation, you’ll have to perform a reset on the watch. In the lower right quadrant you should see a small gold contact on the circuit board with the letters AC (all clear?) stamped on the sheet metal backing next to it. It took a strong magnifying glass for me to see it. Temporarily short the gold contact to the sheet metal backing and the watch should reset itself to 12:00 a.m.

Put the cover back on with the teeny tiny screws and you should be good to go. Be sure to get the o-ring gasket in the channel correctly.


8 Responses to “Replacing the Battery on Your Casio Calculator Watch and Resetting the Watch”

  1. misho said

    thanks, man. You are great!

  2. Harold Mulherin said

    Very helpful! You just saved me the cost of a new watch. Thanks

  3. dan said

    thank you so much!

  4. Dan Powers said

    one thing u are missing is the extra spring. there is a spring inside that goes betweeen one of the contact holes. dont know which.

  5. Grady said

    Thanks, great tip about the AC reset.

  6. Pich Lockoniv said

    ‘Wish I’d read this before I tore into it…
    I couldn’t free the battery clip, so I unclipped the peripheral cage and continued to disassemble…
    Apparently, I was too ham-handed; because by the time I got that battery clip to release, the metal in a little tongue on the clip had fatigued and the little tongue broke off! 😦

    Question 1: Where do I go to find a replacement battery clip?

    Presumably, I’ll be able to stare at an unbent clip and figure out how it routes itself through that white plastic substrate and finds its way back under the battery…

    That clip transfers power from the top (positive) side of the battery to an appropriately insulated circuit-board contact behind (under) the battery. I suspect that previously mentioned little spring completes the circuit by electrically connecting the case to another little contact on the circuit board; but, for the life of me, I can’t figure out:

    Question 2: How is the bottom (negative) side of the battery grounded to the case?

    I can’t see ANY electrical connection between the bottom of the battery and ANYTHING! 😦

  7. Bob M said

    An additional step that is nearly always needed is to clean the “track the seal lays in and to clean the seal ring.

  8. Thank you very much for the excellent instructions , Very easy to follow 🙂

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