C13 100V 1uF at V1(A) cathode , of all things, is highly sensitive to hot
air.
Monitoring the hum over the output load. Once force warmed and hum level
risen it is reluctant to go down again from natural cooling or from freezer
spray - what process is going on with in it?
Now to replace by fudge fitting to in situ component leads or take the whole
thing apart to replace properly?
Marshall saw fit to bodge 3 resistors by cutting off the originals and
flying replacement ones to the cut wires - so whats good for the goose ....