You are a legend JWWebster! You hit the nail on the head for my problem - check the mains filter! I did a test by connecting mains to board missing the filter and bingo works great. No just have to replace filter.
I have an LG WD-1480RD Washer/Dryer. Recently it stopped turning with serious noise (almost grinding sound). When powered off the drum was free to turn. Checked stator windings - all 8ohm so no shorts. Checked wiring to main board everything without success. Finally, removed hall sensor to inspect - nothing obvious. Clipped it back on and machine worked a treat!
Suspect a unbalanced load subjected machine to too much rocking and the sensor may have moved just enough to upset things. Did two loads - worked perfect. Next day went back to do another load and - nothing - machine dead. I figure that when it was having trouble before it was pulling 800-900 watts trying to turn the drum (checked it with a power meter) and perhaps that was the last straw for the filter - finally cacked out.
Anyway, big thanks to JWWebster for suggesting the dead issue was filter related.