Empathy List Archives

PT

Peter Torry

Fri, Nov 26, 2021 2:09 PM

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

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

SM

Scott McGrath

Fri, Nov 26, 2021 2:14 PM

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@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

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

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@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 _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there.

P

perdix@tellink.net

Fri, Nov 26, 2021 2:22 PM

Check this link: https://www.watchuseek.com/threads/seiko-marine-chronometer-qm-10.4913/
It indicates that the QM-10 used a 4.19MHz crystal.

John

----- Original Message -----
From: "Peter Torry via time-nuts" time-nuts@lists.febo.com
To: time-nuts@lists.febo.com
Cc: "Peter Torry" peter.torry@talktalk.net
Sent: Friday, November 26, 2021 9:09:07 AM
Subject: [time-nuts] QM10 Quartz chronometer

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 -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

Check this link: https://www.watchuseek.com/threads/seiko-marine-chronometer-qm-10.4913/ It indicates that the QM-10 used a 4.19MHz crystal. John ----- Original Message ----- From: "Peter Torry via time-nuts" <time-nuts@lists.febo.com> To: time-nuts@lists.febo.com Cc: "Peter Torry" <peter.torry@talktalk.net> Sent: Friday, November 26, 2021 9:09:07 AM Subject: [time-nuts] QM10 Quartz chronometer 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 -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there.

DC

Don Couch

Fri, Nov 26, 2021 3:59 PM

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 Mailhttps://go.microsoft.com/fwlink/?LinkId=550986 for Windows

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

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

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 <scmcgrath@gmail.com> Sent: Friday, November 26, 2021 7:14:04 AM To: Discussion of precise time and frequency measurement <time-nuts@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@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 _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there.

DG

David G. McGaw

Fri, Nov 26, 2021 4:46 PM

But not in a chronometer. They usually use something in the MHz range.

32kHz crystals are not very stable over temperature. Watches rely on
you wearing it for much of the day, keeping it at a nearly constant
temperature and putting it on your bed stand at night, also presumably
fairly constant. Unfortunately they have been adopted for computer Real
Time Clocks, which is why most computers do not keep very good time.

David N1HAC

On 11/26/21 9:14 AM, Scott McGrath wrote:

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@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

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

But not in a chronometer. They usually use something in the MHz range. 32kHz crystals are not very stable over temperature. Watches rely on you wearing it for much of the day, keeping it at a nearly constant temperature and putting it on your bed stand at night, also presumably fairly constant. Unfortunately they have been adopted for computer Real Time Clocks, which is why most computers do not keep very good time. David N1HAC On 11/26/21 9:14 AM, Scott McGrath wrote: > 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@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 > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

AT

Andy Talbot

Fri, Nov 26, 2021 5:39 PM

Some years ago, before we had locked LOs for transverters, the Am.
Microwave community used clip-on crystal heaters. These were a PTC
thermistor with a turnover around 35 - 40C. They were usually used on
5th or 7th overtone crystals around 100MHz designed for 20C operation, so
weren't ideal, but could maintain a crystal more on frequency that just
open to the the air temp.
Perhaps used on a watch crystal thay would work more effectively.

Not sure where you'd get them from now, though.

Andy
www.g4jnt.com

On Fri, 26 Nov 2021 at 16:46, David G. McGaw david.g.mcgaw@dartmouth.edu
wrote:

But not in a chronometer. They usually use something in the MHz range.

32kHz crystals are not very stable over temperature. Watches rely on
you wearing it for much of the day, keeping it at a nearly constant
temperature and putting it on your bed stand at night, also presumably
fairly constant. Unfortunately they have been adopted for computer Real
Time Clocks, which is why most computers do not keep very good time.

David N1HAC

On 11/26/21 9:14 AM, Scott McGrath wrote:

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@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

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe

send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe

send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send
an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

Some years ago, before we had locked LOs for transverters, the Am. Microwave community used clip-on crystal heaters. These were a PTC thermistor with a turnover around 35 - 40C. They were usually used on 5th or 7th overtone crystals around 100MHz designed for 20C operation, so weren't ideal, but could maintain a crystal more on frequency that just open to the the air temp. Perhaps used on a watch crystal thay would work more effectively. Not sure where you'd get them from now, though. Andy www.g4jnt.com On Fri, 26 Nov 2021 at 16:46, David G. McGaw <david.g.mcgaw@dartmouth.edu> wrote: > But not in a chronometer. They usually use something in the MHz range. > > 32kHz crystals are not very stable over temperature. Watches rely on > you wearing it for much of the day, keeping it at a nearly constant > temperature and putting it on your bed stand at night, also presumably > fairly constant. Unfortunately they have been adopted for computer Real > Time Clocks, which is why most computers do not keep very good time. > > David N1HAC > > On 11/26/21 9:14 AM, Scott McGrath wrote: > > 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@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 > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

DC

Don Couch

Fri, Dec 3, 2021 11:45 PM

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 Mailhttps://go.microsoft.com/fwlink/?LinkId=550986 for Windows

From: Don Couchmailto:couchclocks@hotmail.com
Sent: Friday, November 26, 2021 9:00 AM
To: Discussion of precise time and frequency measurementmailto:time-nuts@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 Mailhttps://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@gmail.com
Sent: Friday, November 26, 2021 7:14:04 AM
To: Discussion of precise time and frequency measurement time-nuts@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@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

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there.

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:couchclocks@hotmail.com> Sent: Friday, November 26, 2021 9:00 AM To: Discussion of precise time and frequency measurement<mailto:time-nuts@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@gmail.com> Sent: Friday, November 26, 2021 7:14:04 AM To: Discussion of precise time and frequency measurement <time-nuts@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@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 _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com To unsubscribe, go to and follow the instructions there.

TV

Tom Van Baak

Fri, Dec 3, 2021 11:58 PM

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 Mailhttps://go.microsoft.com/fwlink/?LinkId=550986 for Windows

From: Don Couchmailto:couchclocks@hotmail.com
Sent: Friday, November 26, 2021 9:00 AM
To: Discussion of precise time and frequency measurementmailto:time-nuts@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

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:couchclocks@hotmail.com> > Sent: Friday, November 26, 2021 9:00 AM > To: Discussion of precise time and frequency measurement<mailto:time-nuts@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 >

PT

Peter Torry

Sat, Dec 4, 2021 11:21 AM

Good morning,

Thank you to everyone who has replied both on and off list - much
appreciated and as usual a wealth of information.

My apologies for the late acknowledgement but storm damage had taken out
the phone and internet for nearly a week.

Regards

Peter UK

Good morning, Thank you to everyone who has replied both on and off list - much appreciated and as usual a wealth of information. My apologies for the late acknowledgement but storm damage had taken out the phone and internet for nearly a week. Regards Peter UK