[tdm757]

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.

[PS Staff - Sheila]

If the complete unit is dead then it is the fuse that has opened.

Here is a link to your microwave model MH6151XHT1.

[tdm757]

Originally Posted by PS Staff - Sheila

If the complete unit is dead then it is the fuse that has opened.

Here is a link to your microwave model MH6151XHT1.

The line fuse has continuity. Any other ideas?

TM

[PS Staff - Sheila]

If the fuse in the microwave, number 14, is good it could be the thermal disk,number 7, that has failed.

[tdm757]

Is the thermal disk a thermostat? Would that cause the the control board to show no lights/life?

TM

[PS Staff - Sheila]

Yes the thermal disk is a thermostat.

Usually the thermal disk will stop the microwave from heating but there is usually still power to the board.

You will have to check to see where you are loosing power.

[tdm757]

There is 120V going into the control board, but I can see any life, or 120V coming out into the transformer.

TM

[PS Staff - Sheila]

It sounds like the board has failed.

[Larry42]

I have a similar MW & the MGT failed. It is a pain to get to. You have to remove the outer case then the black plastic inner top; the MGT is screwed to the bottom side of the plastic. The MGT one my MW had this printed on it - SL96A. 250V 10A. 109*C The oven thermostat is also in the same line to the rest of the unit so it could also cause the same problem.