Phil Hobbs wrote:

I'm building a demo system in my lab, and not one, but _both_ of my
HP3325A synthesizers went flatline.

One had almost no output, missing attenuator steps, and distorted wave
shapes, and the other one flunked two of its three self-tests. Not good.

Turned out that ripping out the relay boards and cleaning the contacts
and connectors with DeOxit fixed both of them. (Score.)

(Thanks to the estimable Herbert Susmann for his web page.)
Yup, some years ago I rebuilt an HP 5100A synth (the original 1964 model
that took up about 2 feet of rack space.) It had hundreds of PNP Germanium
transistors in it, and about 15 of them had gone bad. I flipped it on eBay
as soon as I got it working, before any more transistors popped. Silicon
UHF transistors were a beautiful drop-in replacement. The rows of selector
button switches were also somewhat flaky.

Jon