I've been away from this great forum for a while (sidetracked with some other projects) and I think my brain has become addled in the interim...(or maybe it's aging?)
I'm working on a 2235 for my brother-in-law. The right channel is passing way too much DC (1 to 2 volts at the amp PCB output) and consequently won't come out of protection.
I have checked all the transistors using a DCA55 tester and all test fine. I did not verify balance of Hfe for the differential pair.
I'm getting some very wrong voltages at key spots, and they are not stable - some in fact changing too fast for my DMM to register. For example:
H702 emitter = 6 to 11 VDC
H704 base = 10 to 12 vdc
H702 base = 10 to 12 vdc
I'm attaching the relevant part of the schematic and would greatly appreciate any suggestions so that I can avoid removing every component for testing.
Thank you.
I'm working on a 2235 for my brother-in-law. The right channel is passing way too much DC (1 to 2 volts at the amp PCB output) and consequently won't come out of protection.
I have checked all the transistors using a DCA55 tester and all test fine. I did not verify balance of Hfe for the differential pair.
I'm getting some very wrong voltages at key spots, and they are not stable - some in fact changing too fast for my DMM to register. For example:
H702 emitter = 6 to 11 VDC
H704 base = 10 to 12 vdc
H702 base = 10 to 12 vdc
I'm attaching the relevant part of the schematic and would greatly appreciate any suggestions so that I can avoid removing every component for testing.
Thank you.