I've read volumes about the causes and effects of a toasted screen grid resistor and after some testing, i have figured out that my buddy's 74 bassman must have fizzed out because of power tube failure, taking the 470 ohm resistor with it.
I've biased plenty of times before so after the soldering is done it'll be smooth sailing. I just setup an order at mouser for a couple of ohmite 3 watt 470 ohm resistors and 3 watt 100 ohm resistors, and i'll be ordering sprague atoms for the cap job. TAD 6l6wgc's will be going in there once all is done.
Any amp gurus out there that could give any suggestions to why else that screen resistor might have toasted? If not, as soon as those resistors arrive, it'll be show time.