[time-nuts] 5061A Manual Part Number

John Miles jmiles at pop.net
Sat Jun 12 06:33:09 UTC 2010

> Does anyone know the latest 5061A Manual part number and latest
> print date?

I haven't seen anything after the 1978 edition that Had mentioned.  If you
have a newer model 5061A (e.g. with the 10811 upgrade) you might look for a
5061B manual as well.

> I have a 5061A that appears to be working correctly except there is no 2nd
> Harmonic indication.  In addition, on the A7 assembly, there is
> no sine wave
> out on J2.  When looking at the cable from the tube to J1, there
> is no sine
> wave there either.

I wouldn't expect to see much on the J1 cable without a sensitive
synchronous detector or something, given the weak signal present there.  If
swapping A7 still doesn't give you a signal at J2 per the manual, I'm not
sure how that could happen if in fact the tube is being modulated properly.

Note that the 2nd harmonic metering circuitry is on A14 (the logic
assembly), not in A7 proper.  So you could try exchanging that module,
too... but the lack of 274 Hz at A7J2 is still a puzzle.  Does the beam
current vary as expected when you tune the OCXO off-frequency in open-loop

> The 2nd Harmonic indication moves when you turn the Loop Gain pot up and
> down but no steady indication of 2nd Harmonic.

Any chance of a noisy/intermittent loop-gain pot?

-- john, KE5FX

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