[time-nuts] HP5065A Rubidium question

David Scott Coburn scotttt at optonline.net
Sun Feb 19 17:41:56 EST 2017

I have an HP5065A Rubidium Frequency Standard which is not working.

All of the oven temperatures look OK.
The power supply voltages look OK.
The ~60 MHz going into the RVFS package looks OK.
The 5.000 MHz and the ~5.315 MHz signals are within a few Hz.  (The unit is running open loop only.)
The A7 AC amp looks to be working OK.
The A8 137/234 Hz signals look OK.
There is 20 VDC feeding the RVFS lamp oscillator.

But, there is no current coming from the photodiode.  (Maybe a few picoamps of dark current, certainly not the expected ~50 microamps of DC, and no 137/234 Hz signals).

It seems the most likely problem is that the Rb lamp is not coming on.  Maybe possible that the photodiode is faulty, or a broken wire, etc.

Any other possibilities I should check before setting off into the innards of the RVFS package?

Thanks in advance!



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