If you do remove the PA board to get to L305 to remove it, can you do a ringer test on the transformer to see if it has any shorted turns? With the level of power normally passing through L305 it is a possibility. If then the results are not conclusive, maybe someone in the Group that has a PA board can test their L305 and then compare waveforms for the number of rings above the same cutoff voltage.
?
Geoff
