There are a number of things that would case 10 volts on a channel. Look for any cracked traces,cold solder joints, broken leads especially Q104. If you find any failed transistors, its best to replace the remaining transistors as you did with Amp2.
I'm wondering if no output on Amp3 and Amp4 are an input problem. You may recall that the rear channel inputs are on the sub board. If you have signal to the sub board, check to see if the 4558 IC's are getting their +/-15 volt rails. If not check R193,R194-2.2Ω. One or both may failed and will not pass the 15 volts to IC's.
When you say the fets are getting hot, are you referring to the power supply mosfets? The output transistors are BJT's and will get extremely hot.
I'm wondering if no output on Amp3 and Amp4 are an input problem. You may recall that the rear channel inputs are on the sub board. If you have signal to the sub board, check to see if the 4558 IC's are getting their +/-15 volt rails. If not check R193,R194-2.2Ω. One or both may failed and will not pass the 15 volts to IC's.
When you say the fets are getting hot, are you referring to the power supply mosfets? The output transistors are BJT's and will get extremely hot.
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