[time-nuts] HP 5065A Start-Up

Jim/Anna McIntyre bbimini at gmail.com
Thu Dec 10 22:37:40 EST 2015


Turns out there have really just been two major issues so far with this
new-to-me instrument.  As I noted a few days back the pots on the A3
multiplier were intermittent, and twiddling them a bit got the instrument
to lock up.

But it was off by about 77E-10.  The mag field control had no effect.  This
instrument has Option H52.  I've just learned this means the front panel
mag field control is only there to fill up a hole in the panel.  The
control had been re-wired to a spare pin on the rear-panel DC power jack.
All fixed now, and the mag field control works as it should.

I ran through the RF alignment of A3, and all seemed OK there.  Same for
the Phase Detector, Integrator and Loop Gain alignment.  All good.
Except...

Microphonics.

What's the norm here?  I see it in the 2nd harmonic level on the panel
meter.  It runs about 20 normally, but a pretty light tap (with my
fingernail) anywhere on the instrument can peg the meter for a few
seconds.  While I had the scope on A8 TP2 / TP3 (showing the off-resonance
phase shift peak it manifested as bursts of noise) It's hard to localize -
but I think the RVFR and Synthesizer are the most sensitive.



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