Smoke from Bosch Exxcel 1400?

Problem with a Bosch Exxcel 1400 (WVT2850GB/02).

During a wash, my machine started smoking from the back and tripped the house circuit breakers. Looking inside, the connector behind the wash select dial has melted, so some serious current has obviously gone through there. The connector would appear to be for the main power switch, since it has live/neutral wires going into it. I'm guessing the problem is elsewhere and the switch connector was simply the first casualty of excessive current.

Heater element measures around 24 ohms, so that's not shorted. I don't know exactly what it should read, but 24 ohms sounds about right for an element.

If the machine is repowered, it does still seem to work and can be switched on and off via the dial. What I've not done, for obvious reasons, is tried to go through any sort of cycle - however, a brief burst on 'drain' showed the water draining okay and the drum still turning.

I have recently replaced the carbon brushes on this machine, but since the motor is still working, the problem would seem to be unrelated. The machine managed 3 washes with the new brushes before going up in smoke. Perhaps something has been disturbed while moving the machine around to get at the brushes?

Does anyone have an suggestions for fault finding? The temptation right now is to try various parts of the wash cycle while poised to cut the power at the slightest sign of a problem.