[murphyv310]

Hi PJL
Of course the dampness effects the inductance of the tranny, but what I dont really understand why it changes when warm, is the molecules of the water moving in sympathy with the line frequency and turning to vapour (steam) but are trapped in the pitch/varnish etc of the transformer, is the main problem in the overwind or the primary, snag is these faults were rare at the time the sets were in common use.
I've even sealed one of these tranny's in a bag with silica gel and the saturation remains so far heat only works for me, perhaps a dessicator would work perhaps someone could try it!