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Precision Clock - Troubleshooting a single segment for 3 final digits
aesoprrp Posted: 23 Jan 2023, 01:01 AM
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Posts: 2
Joined: 23-January 23
Hello!

I recently performed a repair job on my Precision Clock. The GPS module's connection was flaky, and I needed to gain access to the interior side of the board in order to re-solder the GPS header connections.

In order to do THAT, I needed to de-solder the "seconds" digit and remove it from the board.

I successfully repaired the GPS module's connection, and I re-soldered the single digit.

Upon powering the clock up again, the bottom-right segment does not illuminate in the three final digits.

(User posted image)


I verified whether the segment works at all by using a 3v CR1220 battery connected to the middle pin and each of the segment pins, and all three digits are working properly on their own.

I also verified that the traces from one digit to the next are intact by using a multi-meter set to continuity. And again, confirmed.

If I short the connection from the bottom middle pin of the "seconds" digit to the 4th pin (directly adjacent), the malfunctioning segment illuminates on the next two digits, but not the "seconds" digit. If I perform the same short on the "tenths" digit, the "seconds" and "millisecond" digits work properly, but not the "tenths".

My electronics experience is admittedly limited, but I made it this far! When I repaired the GPS module connections, I did not touch any of the other solder points (as far as I know). I fear that I may have damaged the circuits beyond repair somehow, but I'm obviously hoping there is a simple fix that I'm overlooking.

Does anyone have any idea how to find the fault in the circuit? And maybe an idea on how to fix it?

Thank you!

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aesoprrp Posted: 23 Jan 2023, 05:01 AM
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Posts: 2
Joined: 23-January 23
Problem solved.

I accidentally damaged the trace leading from the faulty segment's pin to the next two digits. The damage was enough to keep the segment from illuminating, but not enough to fail a continuity test.

I have fixed the problem by soldering a small length of insulated wire from the /timeC pin on the "minutes" digit to the /timeC pin on the "seconds" digit.

Many thanks for the detailed wiring diagrams!

https://mitxela.com/img/uploads/clock/mk3/clock3-bom.html



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