Casio 95QR-33 Reset?

[jadney]

I decided to start a new thread with a more appropriate subject.

I've been trying to repair my old Casio 95QR-33. I know that it's not considered to be at all special, but I bought it in Japan in 1980, so it has sentimental value to me. It's actually been a great watch for me, because it has a dual time zone function which has been great when traveling.

A year ago I replaced the 32,768 Hz oscillator crystal and that restored operation after I dropped the watch. Following that, I was able to adjust the oscillator frequency so that it was much better than when new, better than 2 seconds per month.

Last month, however, the display went dim and then disappeared. Replacing the battery did not help. When I took the module apart I found that my crystal solder joints had come loose, so I refreshed them. That brought the display back to bright, but now most of the time the display is nonsense.

Here's what I see:

For 1 second it will display a time, then for 9 seconds it will display random meaningless segments which change every second. Then 1 second of time again, but a time that's 10 seconds later than 10 seconds ago. So it's keeping time, but the display is "confused" for 9 out of 10 seconds. If I R/R the battery, it does the same thing, but the "good" second is randomly on a different digit. (ie I see 04, 14, 24, 34, 44, then R/R the battery and I may see 07, 17, 27, 37, etc. Each time these are 10 seconds apart.)

I understand that the module may need to be reset and that the usual reset procedure is to short + to AC, but there's no AC marking on this 95 module.

There are 4 test points on this module, all on the back. 2 are near the trimmer capacitor and 2 are about 180 degrees from the trimmer. In each location one test point is square and one is round.

I have tried shorting each one of them to the battery +. Let me know if this is wrong.

I have tried disconnecting and reconnecting the battery, since I seem to remember that this helped one time before.

Here are my questions:

Does my description sound like a module in need of reset?

If so, how?

By shorting other test points have I damaged this module?

If this module is now junk, what are my chances of finding a replacement module? Where?

thanks,

[charger105]

Not many people on here know specifics about Casios. You might get a better response here:

http://pocketcalculatorshow.com/eve/ubb ... &f=4111001

I've seen LCDs that behave similarly to what you describe as they try to 'lock-up' to an off-frequency oscillator circuit. They'll display for a second, then pulse/flicker random digits, then try to display correctly again etc.

You may have damaged the QC when you re-soldered it, or even got flux somewhere in the oscillator circuit. I'd suggest cleaning around the QC with isopropyl alcohol, and then replacing the QC again if necessary.

Rgds.