Purchased an MCO165UB microwave 7 months ago. Ran great for 6 1/2 months and then there was no power. No fan, no light, no cooking. It was like the cord was unplugged but the electrical outlet has current. Home Depot exchanged the unit for me. It was installed on Tuesday and it developed the same problem as the previous one on the following Sunday. Ideas?

If the product is 7 to 10 years old than there is chance of low magnatron power check with the replacement.

If purchased "new" 6 months ago, it should still be under warranty. Call repair service....

Hi,

Is the unit plugged in and is the light on inside when you open the door? If so you could have a blown fuse. The cabinet must be removed before you can replace the 20 amp fuse. Good Luck

I’m happy to help further over the phone at https://www.6ya.com/expert/gere_bf68e6055dd61249

Sometimes that is a fan switch to turn on the blower if it gets too hot when cooking on the stove top. But you say the schematic shows it should be closed. So jump it and try the unit. if it works OK then replace it.

The magnetron is shorted or the inverter board is defective if microwave is 7 years old or less.

If the oven is set up to vent outside, then the metal mesh grease filters are used, and they should be cleaned in warm soapy water whenever they look greasy or dirty.

If the oven is set up to recirculate, then the charcoal filter is used, and it must be replaced (not cleaned) every 6-12 months, depending on use.

This model does not have a separate cooling fan like most other models. It replies on the vent fan for magnetron cooling, so if the filter(s) gets too dirty, it can reduce the cooling air flow, which can allow the magnetron to overheat and be destroyed.

I would need to know a little more to help narrow down the "no heat" problem.

If the cooling fan, turntable, and inside light all come on when you press "Start" to cook, then I would ask if you here a "thump" when you press "Start."

If so, then the high voltage section is getting energized. If not, then it may be the cook relay on the control board, which I can affordably repair.

The support page for your oven is here, and it has manuals and part lists you can download.

For more free DIY and other help & advice, feel free to contact me with your full model number and FCC ID number from the tag on your oven.

William E. Miller, AS-EET
[email protected]
http://www.microwavecontrol.com
Microwave Oven Control Panel Repair Nationwide
"Recycling by repairing since 1982"

The charcoal filter must be changed every 6-12 months, depending on how much and how the oven is used.

If a filter clogs, it will interfere with cooling and lead to magnetron damage.

It may also be putting a strain on the cooling fan or hood vent exhaust fan, or one of those fans may have a blade loose on the motor shaft.

You can usually find helpful exploded view diagrams and order parts (including filters) by entering your full model number here.

this would be the digital control board that would need to be replaced

If your microwave oven is ONLY 1 month old and there is any question with its performance, it should still be under warranty from the manufacturer so I would bring it back to where you purchased it and have them provide a replacement of have them demonstrate that the one youi have is working to spec. Conversely, if you put large potatoes in the microwave, they havea lot of mass to them and will need to cook for quite a while.. Have you tried anything else in there of smaller proportions and those did not cook? You should be able to boil a cup of room temp water in a minute or two.. If that fails.. bring it back..

Hope that helps

Popcorn is heated by a metallic insert in the bag. This causes some additional power consumption by the magnetron. It is no cause for alarm.