I have a Univox Amp I purchased off the back of a guy's truck. It powers on,
but all I get is a hum output. I attach a microphone or guitar cable to any
of the inputs and *nothing* changes the output sound. The volume control
doesn't change the level of the hum output either. I should say, I've been
around guitars and amps for about 20 years and the output of this sounds
normal, not necessarily a "hum". It soulds like a normal amp with the input
(guitar or mic) turned off. I've tested all transistors with a VOM and they
seem OK. I've cleaned all pots/boards contacts with contact cleaner. I do
not have a o-scope or a signal generator, so I realize troubleshooting will
be difficult. I do have a schematic. My question is this: Do any of you
have advice for troubleshooting this with just a voltmeter?