You have a bad connection. Do the wiggle under lid bit again, But pay attention to the one that gets it going. ONE wire at at a time. The one that gets it going is loose connection. UNPLUG the M/C from mains. Then disconnect the offending wire. Probably a spade connector, THEN using something like pliers. squeeze in the sides, that will tighten the fit. Refit, plug in and try, keeping hands well away. Probable area is the power input, mains filter section. usually at the top of m/c which is probably where you checked. Keep one hand behind back. Use other to check the connections, Touching wires is not a problem, they are insulated. So nothing to be scared about. Keep using one hand, to check. One hand behind back, means that you cannot complete a circuit, Unless stood in a puddle of water in bare feet. (YOU could safely take hold of a live wire, AS long as you do not complete a cct.) So one hand behind back.
SD, July 2012