[time-nuts] Re: QM10 Quartz chronometer

[Andy Talbot]

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 at 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 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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