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HP8753E OPT 011/006 + HP85047A power up anomaly

Question asked by CharlesB on Nov 4, 2015
Latest reply on Nov 17, 2015 by drkirkby
Hi,
I recently bought a used 8753E opt 011/006 and 85047A and I have noticed the following at power up.

Switch on power
test box doubler LED is on, signal into Port 2 LED is on
self test passes
doubler LED goes out  (relay goes clunk), signal into Port 1 LED comes on
CAUTION: PHASE LOCK CAL FAILED appears for about 1 sec
VNA then runs normally.

When I do a PRESET there is no CAUTION and the doubler is never engaged.

If I connect Rout via an attenuator to R and power the unit on there is no CAUTION.

It seems a bit strange that the doubler LED is on until after the tests complete, my understanding is that 
the doubler isn't used with the 8753E.

Is this normal, or should I worry?

- Charles  

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