Rectifier Arcing problem

[The Dude]

It's more than likely arcing and not detectable via resistance measurements. Have you tried unhooking the secondary? If it's arcing to the secondary, unhooking it and removing the ground path might tell you what's going on. Of course it could also be arcing to the chassis via the iron.

[Enzo]

OK, I got it wrong. I kept seeing "I disconnected the primary" but was reading that as the end wires.

The problem you are chasing it blowing fuses, not bada sound. SO as an experiment just about any OT will do. It doesn;t matter if it changes the tone, at this point all we really need it to do it function and not blow fuses. If that determines the original OT was bad, THEN we worry about getting a more proper OT.

[Chuck H]

With the primary side of the OT primary leads disconnected from the tube sockets, I still get arching

If this is happening as it was written then there is reason to suspect the HV rail or something connected to it OTHER than the output transformer.

[g1]

I think that was with the OT primary CT still connected but plates disconnected. ? If so, OT still suspect.

[hughesp]

Yep - that's what I meant..

Anyway, I replaced the OT with a spare I had lying around and the problem is completely solved.