Microwave has intermittment power. Will start sometimes. Othertimes not at all. Any idea what the problem could be?

The symptoms would seem to indicate a short caused by moisture on the circuit that supplies power to the fan.

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Remove the bottom cover to the oven and check to see if a rubber belt exists, if so it may have stretched and may be slipping. Replace the belt if one exists.

Hi Ben,
This has got to be an intermittent power to the control PCB problem. The control board asking to set the clock means that the CPU has been reset by losing power. First, make sure that the problem is not the outlet by plugging in a small lamp or digital clock to see if it works intermittently or resets. Leave it plugged in for at least 24 hours.
(If using a lamp, put in a small 20 watt light bulb or CFL).
It could also be a bad connection to or at the fuse holder in the microwave oven. If all of the wiring and connections look good, it's most likely a bad connection on the control PCB probably around the transformer on the board. Be careful.......

Great news

The problem is most likely a intermittent keypad control board, but it would be a good idea to call in a professional to verify that.

Hi,
Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Basic Microwave Oven TroubleshootingTips

heatman101..,;';'

Doug, not not attempt repairs on your m/wave unless you have had training.
When you take off the cover even with the plug turned off, their is still charge inside the m/wave which could kill you!
sounds like the magnetron may be faulty, get your approved engineers to carry out a' power check' on the magnetron etc,

Not the magnetron if intermittent. Probably a bad smartboard. Easy to replace if you know the basic precautions to take.

Does this happen just at the full power microwave cook setting?

Have you tried defrosting and doe sit do it on this setting? Does it run any longer in defrost mode?