[Boatanchors] HP 8601A Sweep Generator repaired!

[Arthur Shulman]

Many thanks to all those who replied with help & suggestions. I
considered their advice and finally decided that there was indeed a
problem. (Some readers thoughtfully suggested that this instrument is
not in the same category as a standard signal generator, and I respected
their good opinions.)

A bit of work with a scope and the schematics offered a diagnosis of
excessive voltage drop across a narrow PCB trace, causing the undesired
FM hum. There appear to be several variations of these boards, so
perhaps HP addressed the problem in a later run.

If any readers would like my eventual solution, please email me
directly.

Once again, many thanks to those who offered advice, without which I
might not have investigated further.

Arthur Shulman