I had a working ra-1412 that ended up blowing three output transistors. I have gone over and over it and I feel like I am running in circles. Transistors, emitter resistors, and everything I test seems fine. Then I discovered if I unhook e1 wire from the right main amp board, no short. E1 is connected to the phono board. Should I be looking at the phono board?
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The schematic in the service manual shows E1 being connected to the volume board, not the phono board. E1 shows connected to the shield of the cable, with pink and white wires in the cable. E1 is a ground plane.
Did you run thru the troubleshooting steps in the service manual first?
Did you run thru the troubleshooting steps in the service manual first?
it's too short as a fault description and diagnostic attempt but have you tried with a single RCA signal at a time (two channels powered but the signal only connected to left or right?)
Found a bad transistor, then a bad solder that was shorting to another lead. Now I have good dc reading on output. The remaining issue is it is biasing super high with no control. It is biased at 230mv and VR 602 adjustment does nothing. Replaced the vr and no change. Feel free to weigh in. I suspect this was the issue that blew the outputs in the first place.