1988 Carvin X-100B 4-6L6's

[jnl636]

Output tube don't glow at all. No sound. replaced tubes. 7 vac across pin 2 and 7. Plate pin 3 =483v, Pin 4 grid =480v. pin 5 control grid -51v pins 1 and 8 grounded. Any thoughts?

[Amp Kat]

You may have a bad tube socket or connection on the first one that feeds the others on the traces. Those sockets are not the best as they are pcb mount plastic. Check your screen resistors also as it can keep current from flowing thru the tube.