"CJT" wrote in message
...
tempus fugit wrote:

Thanks for your reply.

Sorry, here's some more info:

There is a power transformer.
Only 1 diode that I could see.
Measured voltages at cap in question was ~150v.

If the cap had DC on it, the diode is probably ok. The capacitor(s)
could be dried out (although I think you said you checked them, so
that's not too likely). From there, you move toward shielding type
problems as already described elsewhere in the thread.

Only 2 tubes - 12AX7 and can't remember the power tube offhand.

If one of the tubes had an internal heater-to-cathode short (or for
that matter, a short at the tube socket), that could cause a lot of hum.
Such shorts are not uncommon.

At any rate, now you have plenty of ideas to consider.

There was also some small device which I assume was a transformer that
hadd
100mA marked on it. It looked like a trasformer with cooling fins.

possibly a selenium rectifier. back in the old days they hadn't figured out
to make high voltage silicon diodes yet.

the usual warnings about selenium: emits poison gas when it burns

replace with modern diodes is recommended.