Good evening,
I have an SSE that is about 6 years old now. Recently it started red plating one power tube, does not take very long after turning on to blow the fuse. I have tried the obvious things such as a new tube, put in a new coupling cap, and replaced the bias resistor. Unfortunately it is difficult to get readings with the multimeter because the fuse blows pretty quick after start up, maybe 15-20 seconds if cold. Any suggestions of possible causes are greatly appreciated, thanks!
I have an SSE that is about 6 years old now. Recently it started red plating one power tube, does not take very long after turning on to blow the fuse. I have tried the obvious things such as a new tube, put in a new coupling cap, and replaced the bias resistor. Unfortunately it is difficult to get readings with the multimeter because the fuse blows pretty quick after start up, maybe 15-20 seconds if cold. Any suggestions of possible causes are greatly appreciated, thanks!
One option is to disconnect the power, remove the output tubes, and measure the resistance from each pin to ground, comparing between the channels. There is not a lot that could be at fault, have you checked the grid bias resistor? If that has been open circuit then that can have an impact.
Lift one end of the coupling cap that feeds the glowing tube and test. Remove the cathode bypass cap (or disconnect the wire at the terminal at the rear of the board) across the cathode resistor for the glowing tube and test. If either of these caps are leaky, shorted, or breaking down when powered, the tube will draw excess current and red plate.