6G6 Bassman-ish Bias Issue

[Skeeter_pdx]

An amp came to me after a power tube was inserted misaligned, there was an explosion and a smell and sure enough the screen grid resistor was blown to smithereens. I put new 470 ohm screen grids in, went to check voltages, and got -52v DC for the bias on one output tube while the other had -42v. Both of the grid leak resistors measure 220k, and I put in new coupling caps from the PI to make sure there was no DC leakage from an old cap. I’m a little stumped on where else to look for issues. Its not exactly a 6G6, but it’s close enough https://el34world.com/charts/Schematics/files/fender/Fender_bassman_6g6_schem.pdf

[sluckey]

Not much on a real 6G6 that would cause the bias voltage to be different on pins 5. You've already eliminated the coupling caps. Pull the output tubes and recheck the voltage on pin 5 of each socket.

[Dave]

Try a different set of output tubes and see what the numbers are.

Dave