This is my third tubelab amp and the first one not to work correctly on first power up. Since I have never had an issue I am not real sure about how to go about the troubleshooting process.
One channel works perfectly and the other has a very weak output. No fuses have popped. Nothing is smoking. I have swapped tubes between the channels and that did not make any difference.
I checked the cathode bias resistor voltage and I get 10 - 11 volts on all el84's.
B+ is running about 345 volts.
Weak channel: r203=.87v r207=101v
Working channel: r103=.86v r107=na
The rectifier tube arced and the fuse popped so I quit at this point. I must have been cycling it on and off to fast. I have an inrush limiter on hot and one on the high voltage center tap to ground. I will look for another 5ar4.
Does anyone have a suggestion as to what I should actually measure? I am looking at the schematic and guessing as to what is important.
One channel works perfectly and the other has a very weak output. No fuses have popped. Nothing is smoking. I have swapped tubes between the channels and that did not make any difference.
I checked the cathode bias resistor voltage and I get 10 - 11 volts on all el84's.
B+ is running about 345 volts.
Weak channel: r203=.87v r207=101v
Working channel: r103=.86v r107=na
The rectifier tube arced and the fuse popped so I quit at this point. I must have been cycling it on and off to fast. I have an inrush limiter on hot and one on the high voltage center tap to ground. I will look for another 5ar4.
Does anyone have a suggestion as to what I should actually measure? I am looking at the schematic and guessing as to what is important.