Quote:
Originally Posted by dieseljeep
You have to check if there's AC voltage on the 12AX7 tube socket. Ordinarily, the pins 4&5 are tied together and the 9 is going to ground.
Is that the only 1st amp tube before the output tubes. One section would be the 1st amp and the other, the phase inverter.
As of now, don't worry about the 220K resistor, until you resolve the 12AX7 heater problem.  |
Well from what I can see of the amp and how its wired currently it doesn't look like there's any wires disconnected from the 12AX7 tube socket, and from what I can see of the schematic glued to the inside of the cabinet the 12AX7 is just a preamp/phase inverter tube in the circuit (its a push-pull 6V6 hi-fi mono amp so its not stereo so it only has one 12AX7 that is divided into to sections section 1 being the preamp stage for the phono pickup and the second section being the phase inverter stage for the audio amp stage for the push-pull 6V6s.
anyways like I said I'm really not sure as to what could be causing the 12AX7 to get no power because its got all of the connections to the socket intact from what I can see...
EDIT: Just noticed that the 12AX7 tube socket is suffering from Cadmium corrosion (where the Cadmium Plating they used to plate the contacts on the tube socket turns into a fine yellowish colored powder on the socket) I wonder if that Cadmium corrosion is what's causing the 12AX7 tube to not work right.