Steve wrote:

We have an HP 8640b that will not work in phase lock mode. When you
turn on phase lock, the unit tries to phase lock for about two
seconds, then the display blinks. It does this on all frequency
ranges. Looking at the output, when phase lock turns on, the signal
jumps up in frequecy and keeps climing until the display blinks, then
the signal returns to the original frequency. I haven't opened this
one up yet, figured I'd ask if this is a normal problem before I dig
in.

I have checked for the obvious problems, i.e. cracked gears, loose
boards, burnt components..

All help appreciated.

Thanks,
Steve
open the lid, look in the back, there is a power supply board plugged
in, actually boards! , they have LED's that indicates them being on.
you mostly will find one not on. flip the unit over, remove the bottom
lid, there is a can transistor there that likes to have it's screws in
the collector come loose. Tighten..
I have 2 of those units with all the options, they both have that
problem at times.



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