[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




More information about the Time-nuts_lists.febo.com mailing list