Whirlpool AKZ electronic ovens

Hi,
Just as a help to me an others who don’t do too many of these;
Had one a few weeks ago, dead, single pcb behind facia. Found broken track to the transformer, repaired.
Went to one last week, dead, had two pcb’s. Both looked ok, customer buying a new oven. Which pcb (power or display) is most likely to cause this?
Any advice is appreciated.

Thanks
Graeme