Ok, i did more testing, there are in fact no Transistors in this amp, however there are 4 diodes that look similar to transistors,the 400v diodes/rectifyers and they are putting out the needed 400 Vdc, pulled out the scematic and traced out the whole biasing paths on the bad tube and checked all the components and even did voltage tests and comparisons to other tube biasing paths and found everything to be good, i even tested the bad tubes biasing potentiometer powered on and it is putting good voltage that varys with the potentiometer movement to the tube,checked the voltage after the capacitor that is in the biasing path its good,ohmed out the tube base and checked for continuity on all contacts, partially placed the tube in the socket and checked for continuity between the base and the tube itself, i swapped tubes again to double check, same problem, not even reading .001 Vdc at the bad tubes biasing test point, checked the biasing on the other 7 tubes, there still fine.
wow, this has to be something strange with the tube socket, i may swap 2 sockets out to see if the problem moves!
It would be virtually impossible for it to be anything other then the tube socket! i checked everything that has to do with the bad tubes biasing circuit.
will keep posted.
wow, this has to be something strange with the tube socket, i may swap 2 sockets out to see if the problem moves!
It would be virtually impossible for it to be anything other then the tube socket! i checked everything that has to do with the bad tubes biasing circuit.
will keep posted.
