Over the Range Microwave went dead while exhaust fan only was running. No power at all going to unit. Control board has no function working or showing signs of power. In the inside of the computer control panel there is a wiring diagram, and based on the wiring and testing criteria; the thermal fuse, capacitor, diode, fan motor, and on the transformer, the primary and filament wiring test ok. I didn't test the secondary wiring of the transformer, as it is covered with a tape protective covering.
There is a MGT THERMAL FUSE shown in the wiring diagram, but I can't find it. Could that be the issue?
The secondary switch didn't doesn't appear to make contact with the door, so I held the switch down, and still no power to the unit. This might be an auxillary problem.
Is it possible that the $175 control board is dead? How do I test it for sure?
Any other ideas?
This one has been a learning experience for me, as this isn't my cup of tea. This board has been very helpful, and I hope someone can help me.
First change all the fuse and check whether it works or not, if it does not work than as per your finding the secondary transformer could be the issue, the secondary transformer tap down the voltage fro 230-240/110 to required control board voltage. the best thing if the unit is opened then the right problem can be found but as per your description either fuses are faulty or the secondary transformer.
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In my description it says I tested the thermal fuse as ok. I meant the ceramic fuse - not thermal, but electric. The ceramic fuse has continuity.
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