Have you tested the output from the p.c.b to the fan motor before condemning it?
You could test the continuity of the windings on the motor with a multimeter, but please switch off power first, remember what happened the lil mouse.
not sure what the TRIGGER board but i believe the only electronics on this oven is the clock and you say that works. the oven cannot reach the temp unless the fan runs.with the power off try turning the fan with a screwdriver or similar through the back cover it should be free running if not it prob needs replacing