[time-nuts] HP 10811 update

Bob Camp lists at rtty.us
Wed Jul 24 23:45:58 UTC 2013


Hi

The regulator should be fixed, and the OCXO will work better with it repaired. That said, shifting the regulated voltage from 5.7 to 5.27 volts should not shift that oscillator 45 Hz.

Bob

On Jul 24, 2013, at 9:00 AM, paul swed <paulswedb at gmail.com> wrote:

> Hello to the group. Numbers of threads running on the HP 10811. Mine is 45
> Hz low. The oven is most likely ok. I did get the can open per the various
> other threads and the web pix. Started testing the circuits and have found
> that the regulator for the oscillator isn't. Its supposed to produce 5.7V
> and is at 5.27V thats pretty significant. The transistor looks like a
> shorted collector base junction. Though I do not have it out of circuit
> yet. Its Q4 a 2n6429. What interesting about this transistor is its beta at
> 1 ma is 500 min and max is 1300. Its not a darlington. Thats pretty
> amazing. I am looking through my xsistors to find something close. May just
> through a 2n3904 in for a quick test. Its beta is nothing like the 6429.
> But it would help to prove/disprove the point that the low V may be
> offsetting the oscillator I hope.
> Will also embed a K thermal couple to verify the oven really is in the
> 80-84C region.
> Regards
> Paul.
> WB8TSL
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