Re: [time-nuts] HP 5065A Start-Up
> 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. If your 5065A is like most of the older ones I've seen, it has been upgraded with a 10811-60109 OCXO. If so, there is a spring-loaded shaft extension that allows you to access the 10811's calibration trimmer from the panel behind the hinged door. It can be a good idea to remove that hardware, since it can otherwise transfer external vibrations to the OCXO. That probably isn't enough to pin the meter but it's still worth checking. (Be sure to check the ESR of all of the axial tantalum electrolytics on the RVFR oven control board, if you haven't already. A failed oven controller can really hose the RVFR.) -- john, KE5FX Miles Design LLC ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 5065A Start-Up
Jim, > 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. 20 is the border level of the 2nd harmonic (20-40). After some week of continuous operation can happen the signal level increase otherwise an adjustment is necessary. I had the same experience on some HP5065A revived after a long period of inactivity. The microphonics is high during the first few weeks of operation, then later recedes. I could see about a dozen HP5065A that I had in my hands that a reduced microphonics is a feature common to all HP5065A. Luciano > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] > and follow the instructions there. > > > > Links: > -- > [1] > http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma > ilman/listinfo/time-nuts > Message sent via Atmail Open - http://atmail.org/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 5065A Start-Up
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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
