11-06-2023, 03:01 AM
Define acting up? It looks like an AC/DC set judging by the diagram. I'm really just shooting in the dark here without having an idea of what is going on, but if all the capacitors have been replaced, correct values, correct voltage ratings, in the correct places, then it could be something like a gassy tube, or secondary emission from a grid. It also could be that a carbon comp resistor is failing, more voltage, more heat, and the connection inside is breaking down.
Regards
Arran
Regards
Arran