Pretty familiar with building kits/soldering/fixing basic stuff but this is a new level for me. Always wanted to five deeper into understanding more. Unit powers on and left channel is fine but right channel sign very low. I want 2 way channel stereo. I am pretty sure this unit was setup 3 way mono for decades and kinda stuck. LOUD clicks on the LOW on/off switches and mono LOW. Got some contact cleaner coming. No visible issues upon inspection but can post pics if needed. Also have schematic. Anyone willing to help? Many thanks in advance!!!