No more arc

[pavetim]

I'll check those. what else is in the system that's not on the board?

[performance]

Is the wire drive working at all?

[performance]

Never mind, it seems it is.
Pot could be bad.

[Rambozo]

I'll check those. what else is in the system that's not on the board?

The inductors, probably any large output caps, connection straps, etc. Is that a single board unit, or is there a second control board in the front? Maybe take a few pics. Zoama is right, just start tracing and you should be able to locate where the power starts and stops. Be sure to check the terminals where you swap polarity and especially anywhere there is a mechanical connection point.

[performance]

It's a single board. It stands vertical. But you are right, pictures might help isolate or see the problem.