Hi Rob,
From my limited experience I would say please check the PCB around the
heaviest items on the board, clearly typically the transformer. The
4000/60 wouldn't power up (with noticeable noise) and I found that the
solder joint on one of the pins had broken. This took extracting the pcb
from the enclosure which mean unsoldering the inlet
wires, but clearly
it was worth it in the end ;)
Regards, Mark.