DSL40c bias issue

[ledvedder]

Con5 pin 1 isn't reading any millivolts on my DSL40c. Pin 3 is reading fine at 36mV. I've swapped the power tubes around and also tried another set. The issue always stays at pin 1. It's obviously causing a hum. Can someone assist me with what I should look at? Looks like one of the 5W 1k resistors may have gone bad.

 

[blackba]

Here is a link to the schematic. https://music-electronics-forum.com/filedata/fetch?id=837569

I would check the grid and screen resistors, those are R118 and R120. And R114 and R116. Could also be a bad solder joint on one of the power tubes. You are on the right track thinking it’s a 1k 5w resistor, that is R114 andR116.

 

[Madbastard]

Change all the 4 resistors! 1k ohms, 5 watts or more... Try wire wound resistors.

 

[ledvedder]

Yep, I ordered some. Just waiting for them to arrive. I guess the bigger question is what would have caused it to go bad?