AEG lavatherm 57700 dies after switch on

The tumble drier dies about 30 seconds after switching on and sellecting a program. It dies before the start button is pressed.
By dies, I mean all the lights go out and another (or the same) program cannot be selected until the machine has been switched off for about a minute.

I have cleaned and emplied the condenser and water container. Since the condenser was a bit clogged up I checked the pump and it was clear and turns when power applied.
I have also had the circuit board out to check for dry joints or burnouts – none visible.

Does anyone have an more suggestions before it has to be replaced.

Many thanks
Peter