Hi Peter,
Restoration of balanced signals into IC5 pretty much confirms it was damaged to some degree. Put ?in a new chip and check for balanced signals at both the inputs and outputs of IC5 before you add the new finals.
Have you received the transistor caps? It’ll be interesting to see how much they reduce the PA temperatures. JZ’s analysis of package and lead frame heat removal seems to justify adding these caps. Question: with the caps installed, will it still fit inside the closed case?
Tony - AC9QY
I removed IC5 pretty carefully, but apparently I still put too much heat into the finals as they appeared to be drawing too much current again. I removed them and no longer see imbalance at the input to IC5 at least. I'll do some further tests and if everything looks okay I'll try putting a new IC5 and fresh set of TN0110 on tomorrow. This board has been through a lot :|.
