[Radioroslyn]

Hi Dave
You said the magic word so I have to answer!

 <When I tried taking ohm readings on the 50L6GT, I accidentally touched both pin 2 and 3 at the same time and got a loud hum from the speaker.> 

I'll bet you did!!!!! That's like putting 110vac across the output transformer!!! I'd buzz too!!!

So connect the - probe of your volt meter to pin 6 of the 7C6. This is B-. Connect the + probe
to pin 7 of the 35Z3. should see about 100vdc. Then have a look at pin 4 of the 50L6. Should
see about 100vdc. Next pin 3 of the 50L6. Should see about 90vdc.
Report back with results.
Terry