[time-nuts] HP-103AR frequency beyond adjustment
csteinmetz at yandex.com
Thu Sep 28 08:48:17 EDT 2017
> The only thing I've not adjusted is the oven temperature.
> I know there's been discussion of this subject here in the
> past but my searches come up empty—I must be using the wrong keywords.
> The 103AR is just a toy for me so no harm is done if the frequency can't be
> raised to 1 MHz but if it's possible I'd like to try. Have I missed something
To adjust the frequency trim range, replace selected capacitor C103
inside the oven (nominally 18pF). Use a C0G/NP0 ceramic. Note that HP
indicates this "Component [is] not separately replaceable." But at this
point (nearly 60 years on), opening sealed oven assemblies has become
routine for those who maintain old HP standards.
The procedure for adjusting the oven temperature is described in
paragraph 8-11 of the operating and service manual 01037-2 (printed Jan
1962). Be advised it is somewhat tedious.
If you do not have the manual, you can download it here:
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