U12 is a MC14060B. Link Below. U14 is a LM361. Link Below.
U12 is an squarewave oscillator.U12-Pin 5 feeds Pin 2 of U13-TL072C. Pin 1 of U13 feeds the base of Q103-3875GR. C266-47p at the base of Q103 integrates the squarewave and generates a triangle wave.
You should see a triangle wave at Pin 4 of U14 comparator. Pin 3-U14 is the signal or audio input. Pin 13-U14 should be the composite squarewave and audio.
If you have an oscilloscope look to see if you have the triangle and squarewave at the Pins I mentioned. Post screenshots. Also, measure the DC voltages around U14 using the negative speaker terminal for black probe and scope ground. Post the results in the following manner:
I posted your pic of main board, that's been cropped. Please take a close up of this area and post. I tried to magnify your pic, but not able to without pixalation. I will be able to edit pic and point out test points etc
The U14-LM361 may have failed. Replace if you haven't already. Also, check the DC voltages across D107,D108,D120,D121.
When I power up the amp without the output fets I'm getting positive and neg rail on the both outside fet leg pads of both the pnp and npn banks. When I put 1 fet in each bank the amp cycles in and out of protect rapidly. I dont know what the next step is or where to look
sorry. I meant n fets and p fets. When I put 1 fet in each bank the amp cycles in and out of protect. I was able to put 1 in each bank of one side and it powered up fine. Then I took them out and put them on the other side and it started going in and out of protect again.