Greetings gents,
I’m helping my buddy with his AA4000. Presently the amp when powered up, channel 2 comes out of protect after 3~5 seconds and passes clean audio. Channel 1 however remains in protect. I’ve tested the output transistors for shorts, none found, all small semiconductors tested ok, bias set the same as the right channel across the emitter resistors. There’s approx 9mv of DC at this point before the relay. Channel one passes clean audio up to the relay, the relay however is not engaging. I pulled the relay and checked, tested fine out the PCB. I then went back through the protection circuitry but didn’t find anything on the second pass. Transistors tested ok, replaced the caps.
I’m a bit more frequent on the car audio pages/amplifiers but I decided to give this a go.
Has anyone experienced this before, or can suggest anything I’m overlooking?
I’m helping my buddy with his AA4000. Presently the amp when powered up, channel 2 comes out of protect after 3~5 seconds and passes clean audio. Channel 1 however remains in protect. I’ve tested the output transistors for shorts, none found, all small semiconductors tested ok, bias set the same as the right channel across the emitter resistors. There’s approx 9mv of DC at this point before the relay. Channel one passes clean audio up to the relay, the relay however is not engaging. I pulled the relay and checked, tested fine out the PCB. I then went back through the protection circuitry but didn’t find anything on the second pass. Transistors tested ok, replaced the caps.
I’m a bit more frequent on the car audio pages/amplifiers but I decided to give this a go.
Has anyone experienced this before, or can suggest anything I’m overlooking?