[time-nuts] Continously drifting HP 10811...

Ulf Kylenfall ulf_r_k at yahoo.com
Wed Nov 8 12:24:06 EST 2017

I am about to try to repair a second 5065Aand have now tested a number of 10811 Quartzoscillators that was in the junk box.
In order to test the 10811, I put them it in a chassisthat is used for GPS-locking. Adjust for lockand then monitor the EFC-voltage over time.
Starting out with a lock condition and the EFCvoltage adjusted to -2.500V I can see that theoscillators exhibit a monotonus EFC voltagedrift towards 0 volts. About + 1 mV in 3 minutes.
By comparison, I have a 10811-60109that was tested in the same GPS-application andthis unit is rock-steadyand that does not show any sign of EFC drift.
Test time has been 3 Days, and I beleive thata 10811 should have been able to reachthermal equilibrium during this time.
I can and will (of course) take them apart.Anything special to look for other thanthe usual signs of long-term over-heated discretes?
Ulf Kylenfall -  SM6GXV 

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