[time-nuts] HP 10811 40 Hz low.

Bob Camp kb8tq at n1k.org
Wed Dec 14 19:10:56 EST 2016


Crystals do indeed fail. In the case of 40 Hz low, I’d look for a shorted cap in series with the crystal.


> On Dec 14, 2016, at 5:23 PM, paul swed <paulswedb at gmail.com> wrote:
> I have a hp z3801 that is spare parts it never worked correctly. Did some
> digging and at least one major issue is the actually HP 10811 is 38 Hz low.
> It needs to be within a Hz. Checked everything feeding voltage and such and
> they are solid at 5.7V from the regulator. The varicap works as expected.
> Signal levels out are clean and correct. Temp is about 82C also inline.
> The oscillator is actually fairly simple. Do xtals just fail after many
> years?
> May see if I can map a Piezo oven oscillator into the z3801 just to see
> what if anything happens. Now that I know the warm oven signal drops fromm
> 22V to 3.8V when hot. Fake it out.
> Not sure the outer oven actually matters on the z3801. But even that can
> actually be hooked up to make any circuit that might want to know thats it
> hot happy.
> Regards
> Paul
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