The top ones are not important. We are looking bottom ones. Only one, measure, take out, second one, measure, take out...
Can be housing touching heatsing somehow, or screw touching the heatsink. I bolive that is not the case with all four transistors, but one or two makeing problems. Which one?
Only one mesuared shorted,take out not shorted.
Second, mesuared shorted,take out not shorted.....
Third, mesuared shorted take out not shorted
Forth, mesuared shorted take out not shorted
Second, mesuared shorted,take out not shorted.....
Third, mesuared shorted take out not shorted
Forth, mesuared shorted take out not shorted
I veryfied all resistors and all transistors,all ok.
Capacitors ok.
I don't understand......
The rectifier is also ok
I don't can power on the Amplifier no power transformer on board
Capacitors ok.
I don't understand......
The rectifier is also ok
I don't can power on the Amplifier no power transformer on board
The diod D410 tested on Amplifier is bad, shortcut on mass two side with multimeter
But desoldered he is in good working order.
Strange
But desoldered he is in good working order.
Strange
According to your pics in #5 the mandatory isolating bushings appear to be missing.
Best regards!
Best regards!