There are sooo many stages and parts in these nice old generators, it
could be most anything.

If it happens on EVERY range, then it's most likely in the big
rocket-shaped oscillator. Too bad as that's acccording to HP a
non-user-repairable unit.

IMHO the whole thing is a non-repairable unit! There are so many
custom IC's in there it's a big crap-shoot. I was able to make ONE
working unit out of three sick ones, but that's not terribly
economical. The nylon gears, the digital readout, and the voltage
regulator modules, the FAN, the lever knobs, the slide switches, all
seem to be very weak points on these units. They're very ruggedly
built otherwise, lots of gold-plating, heavy-duty castings. But too
many weak points IMHO. You might consider parting it out! I'd sure
bid on a working digital readout module!

Regards,