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Start again by taking another close look for obvious mechanical issues. Do you have any loose wires? Are the connectors seated nice and tight. Are the speaker wire connections tight? Do you have a solid connection at the terminals of the speaker? On the PC board, do you have any funky looking solder connections? Did you clean the pots and jacks with a chem cleaner? And have you tested the amp with another cable?
Make sure you have the correct DC voltages around the amp. The schematic gives you some voltages. Look at those. Check the power supplies at C20 and C21. Check the emitter of Q101. Check the op amps (V+, Input and Output pins). Remove the speaker and check the output. You should not have any dc voltage on the output. Until you know this for sure, I would keep the speaker disconnected. Recheck just to make sure all is well.
Be careful of the input signal. Do not overdrive the amp. Start with maybe 50mv rms... something like that. Juan suggested 100mv rms at 1Khz. I would check to see if you have signal at the Preamp out. If yes, work your way forward. If no, you go backwards.
As for testing transistors, you can first look at the voltages on the transistors. You should have the typical .7 volt drop from the base to emitter. If you do not measure that and need to check a transistor, I would pull it. You can do a quick check with a multi-meter but I use the ATLAS DCA SEMICONDUCTOR COMPONENT TESTER AND ANALYZER. Easy to use. Watch a YouTube video for instructions.
Start there and perhaps the others can chime in.
Make sure you have the correct DC voltages around the amp. The schematic gives you some voltages. Look at those. Check the power supplies at C20 and C21. Check the emitter of Q101. Check the op amps (V+, Input and Output pins). Remove the speaker and check the output. You should not have any dc voltage on the output. Until you know this for sure, I would keep the speaker disconnected. Recheck just to make sure all is well.
Be careful of the input signal. Do not overdrive the amp. Start with maybe 50mv rms... something like that. Juan suggested 100mv rms at 1Khz. I would check to see if you have signal at the Preamp out. If yes, work your way forward. If no, you go backwards.
As for testing transistors, you can first look at the voltages on the transistors. You should have the typical .7 volt drop from the base to emitter. If you do not measure that and need to check a transistor, I would pull it. You can do a quick check with a multi-meter but I use the ATLAS DCA SEMICONDUCTOR COMPONENT TESTER AND ANALYZER. Easy to use. Watch a YouTube video for instructions.
Start there and perhaps the others can chime in.
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