Yes, I placed Don's QM10 photos and IC pin analysis here:
http://leapsecond.com/u/couch/
FYI: the link below is badly mangled due to his email client or ISP or
Outlook. It is not a time-nuts server problem. Please do not click on
links like that.
/tvb
On 12/3/2021 3:45 PM, Don Couch wrote:
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
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
From: Don Couch<mailto:[email protected]>
Sent: Friday, November 26, 2021 9:00 AM
To: Discussion of precise time and frequency
measurement<mailto:[email protected]>
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
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