[462ron]

Hi R3, just glancing over the schematic,if C1 and C2 are good and they appear to be by the voltage you are getting on TP 18&19, then I would check X6, the output transistor next, the big one probably mounted on a heat sink. It would appear that if it were shorted, it’s the only transistor that would pull enough current to melt wires as it only has a .68 ohm resistor on the emitter and the output transformer on the collectors to limit current draw, so if shorted would have the ability to put a heavy load on the 12.6 volt supply. The other transistors appear to have a decent amount of resistance in their circuits. Not saying you shouldn’t test those but X6 would be my first one to test and they are known to short.

Ron