I'm working on a QSC USA 370 stereo power amplifier. When I got it, only channel 2 was working.
I found 3 bad output transistors, an open 22 ohm (R 18a) resistor and an open .22 ohm power resistor (R27a).
I replaced all them parts and still nothing out of channel 1.
D 11a and D11b are fine at -15 volts.
D 10a is only at 2 volts when it should be 15 and when I lift the hot side I get nothing.
D 10b is fine at 15 volts.
I don't know much about op amps but could a bad op amp cause this problem? Would I damage anything if I swapped the two to see what happens?
I've checked just about every other component in the amp. All diodes and resistors and transistors seem to be fine. I'm stumped. I normally work on tube amps but due to the economy have had no choice but to start learning solid state repair.
Any advise on what to check next would be greatly appreciated. I can provide a schematic but not sure how to do it on here.
Thanks in advance
I found 3 bad output transistors, an open 22 ohm (R 18a) resistor and an open .22 ohm power resistor (R27a).
I replaced all them parts and still nothing out of channel 1.
D 11a and D11b are fine at -15 volts.
D 10a is only at 2 volts when it should be 15 and when I lift the hot side I get nothing.
D 10b is fine at 15 volts.
I don't know much about op amps but could a bad op amp cause this problem? Would I damage anything if I swapped the two to see what happens?
I've checked just about every other component in the amp. All diodes and resistors and transistors seem to be fine. I'm stumped. I normally work on tube amps but due to the economy have had no choice but to start learning solid state repair.
Any advise on what to check next would be greatly appreciated. I can provide a schematic but not sure how to do it on here.
Thanks in advance