Help with Panasonic SG-K2000/SG-H10 amplifier issues

Hello everyone, I'm having issues fixing this vintage stereo system, its amplifier boards seems to not be amplifying. The audio comes out at super low volume with the max. volume setting (the pot. works correctly). At first I had 20V and a constant hum coming out at the speakers output (saturated amp. I supossed). I changed the electrolytic caps., the 5218P component (TL082 replacement) and the NPN/PNP C1815 and A1015 transistors (this last thing helped with the amp. saturation and I do not have any DC at speakers now), but now the audio comes out super low. I measured the D1265 transistors off-board and they seem to be ok. Can anyone shed some light? Thanks in advance