I have two of these. They are very nice precision chronometers. If I remember correctly, the frequency is 4194304. The oscillator is a TCXO usually in a small round 8-legged can. I have never seen a bad one. The most common problem is the backup battery. If it is still there, it is very old and often shorted. There is a diode in series so if the battery is shorted, it does no harm, but I have seen the diode shorted as well. I do not have schematics, but you can trace the battery circuit.
Don Couch Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows ________________________________ From: Scott McGrath <[email protected]> Sent: Friday, November 26, 2021 7:14:04 AM To: Discussion of precise time and frequency measurement <[email protected]> Subject: [time-nuts] Re: QM10 Quartz chronometer Usually in analog quartz clocks oscillator frequency is around 32khz Content by Scott Typos by Siri On Nov 26, 2021, at 9:09 AM, Peter Torry via time-nuts <[email protected]> wrote: Hello list, I am restoring a Seiko Quartz QM10 Marine Chronometer that is currently inoperative. Preliminary investigations would indicate that the oscillator (TO5 header) isn't functioning therefore I am seeking any information as to its nominal frequency and whether it is just a crystal or an oscillator. I can follow the cmos dividers OK but a schematic diagram would be most useful. Any help or pointers much appreciated. Kind regards Peter UK _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
