[time-nuts] Re: Fw: HP 5065A, no 2nd harmonic.
ed breya
eb at telight.com
Sat Nov 20 04:21:36 UTC 2021
As Corby said, check for the 137 Hz signal first. If that's OK, I think
the simplest thing you can do before taking things apart, is to look at
the adjustment pot for the 274 Hz amplitude. Mark its position, then
tweak it end to end a number (like tens) of times, then back to its
original position. That should eliminate possible pot wiper contact
issues. There's not all that much to the circuitry, and it's an
independent function, so should be easy to figure out - as long as
everything up to the 137 Hz is working OK.
Sometimes bad Ta caps can happen, but HP used the good kind
(hermetically sealed), and it looks like there are none directly across
low-Z supply buses, and some are for signal coupling. It's unlikely any
would be bad here, but possible.
Ed
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