[Big Bad Bob]

On 10/20/16 07:11, Peter Wieck so wittily quipped:
To start, I'm replacing all of the paper electrolytic and non-electrolytic paper capacitors in the amplifier and will go from there. I checked the tubes. They're all good, but the 12AX7s are a little low on emission. The power cord is frayed. I'm going to replace this with a 3-wire power cord.

Before you do this, make sure that the chassis is actually fully isolated - no fault in the transformer and that this is not a transformerless design. Unlikely, but with this sort of thing, adding a 3-wire cord can sometimes have untoward results. If there are line-bypass caps in place, be even more careful, and replace them with properly rated (X or Y) type caps.

I've seen those 'partially short', before. zapped myself on the
chassis. I took them out of the circuit on one unit [long time ago], a
resistor and a capacitor. It worked fine without them.

And check for hum loops after installation. Unlikely, but worth attention.

Hum loops caused by *ahem* those same RC components on the AC line
coming in, effectively putting a signal onto the chassis.

(I have several ground loop isolators on the 3 computers and other stuff
plugged into a mixer board on my desk, for the audio, as those computer
switchers notoriously put an audible signal on the ground, if you have
more than one of them in the same circuit).