[time-nuts] Re: QM10 Quartz chronometer

[Don Couch]

Here is signal data and some pictures from one of my QM-10 chronometers. Curiously, the oscillator only produces 8 Hz. Obviously, it must have a high frequency crystal inside the can somewhere.

I set this clock to the correct time on May 23, 2020. It is now five seconds fast!

Tom van Baak kindly noted the pictures are too large for email, so he moved them to http://leapsecond.com/u/couch/<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fleapsecond.com%2Fu%2Fcouch%2F&data=04%7C01%7C%7Cee0742a79f1e4d8842fe08d9b6abba73%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637741670943146640%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=nNiqsRRttsNVzs88XyMCfeOsqCkRObPymRRRXSw%2BJ0g%3D&reserved=0>
The picture of the top of the board shows the original backup battery, which I disconnected. I added the round blue-edged supercapacitor (0.047 F with the red and black wires) so the main battery can be replaced without stopping the clock.

Let me know if there are more questions.

Don Couch

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From: Don Couch<mailto:couchclocks at hotmail.com>
Sent: Friday, November 26, 2021 9:00 AM
To: Discussion of precise time and frequency measurement<mailto:time-nuts at lists.febo.com>
Subject: [time-nuts] Re: QM10 Quartz chronometer

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://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgo.microsoft.com%2Ffwlink%2F%3FLinkId%3D550986&data=04%7C01%7C%7C8d751e8121534ab444d108d9b0f5e39b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637735392399899177%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=FEO%2FS%2FYmwMp28mghhfOq5L9W2J1HA%2FL%2Bz6sEgQW%2BTro%3D&reserved=0> for Windows

________________________________
From: Scott McGrath <scmcgrath at gmail.com>
Sent: Friday, November 26, 2021 7:14:04 AM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
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 <time-nuts at lists.febo.com> 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
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