Carver PM1.5 problem

[pergo]

i replace suspected output bjt, re-test with multimeter every component and match it with the "good" channel.

Nothing, niente, nada de nada..

I don't have much time to spend, so I give up.

 

[cihtog]

Why are you replacing parts on the output stage, instead of looking for the source of the upstream short?

Did you test the bjt output that you suspected, or just replace them because they looked different?

 

[pergo]

Q14 and Q15 are good, drivers are good, resistor near Q14 and Q15 are good, opamp is good.
The voltage stepper seems good.
What else?

 

[cihtog]

How did you test Q15?

 

[pergo]

remove, measure Vbe with diode check, and Hfe with multimeter. It's good.

 

[cihtog]

Then move to the ground between R17 and R51 - is it good?

Check Q16, Q17, Q18, and Q19 - are they good?

With a dimbulb, are the power supplies on either side of R15 and R52 equally above and below ground potential?

Are R15, R16, R50, and R52 all in spec?

Is RP-1 reading a suitable value across pins 1 and 3?

Is C5 open or shorted? Does your meter measure capacitance? (Most good meters go up to 20uF)
If you can't measure it, does it charge in both directions on the highest ohm setting?
Plan D: replace C5 anyway.

Did you test Q15 across all 3 pins, both directions?