I believe to have identified the chips by elimination based to supply voltages, VCC and GND pins.

IC1 = LM339 or pin-compatible

IC3 = TI5534 or pin-compatbile

I have redrawn and simplified the schematics while hopefully making no mistakes and the circuits seem to become more understandable and sensible:

For now, I won't accept it as answer, but wanted to provide it as potential answer. Should anything change about my assumptions, I will update the post.

I believe to have identified the chips by elimination based to supply voltages, VCC and GND pins.

IC1 = LM339 or pin-compatible

IC3 = TI5534 or pin-compatbile

I have redrawn and simplified the schematics while hopefully making no mistakes and the circuits seem to become more understandable and sensible:

For now, I won't accept it as answer, but wanted to provide it as potential answer. Should anything change about my assumptions, I will update the post.

I believe to have identified the chips by elimination based to supply voltages, VCC and GND pins.

IC1 = LM339 or pin-compatible

IC3 = TI5534 or pin-compatbile

I have redrawn and simplified the schematics while hopefully making no mistakes and the circuits seem to become more understandable and sensible:

For now, I won't accept it as answer, but wanted to provide it as potential answer. Should anything change about my assumptions, I will update the post; particularly after studying the diode in the feedback loop on IC3A.

I believe to have identified the chips by elimination based to supply voltages, VCC and GND pins.

IC1 = LM339 or pin-compatible

IC3 = TI5534 or pin-compatbile

I have redrawn and simplified the schematics while hopefully making no mistakes and the circuits seem to become more understandable and sensible:

For now, I won't accept it as answer, but wanted to provide it as potential answer. Should anything change about my assumptions, I will update the post.