My Kenmore elite ultra wave microwave hood combo shuts off After just 4-5 seconds on High power. It will run fine on power level 1, but shuts off after 30 seconds on power 3. Is there anyway to fix this?

Power Supply module burned out, shorted or blown pcbs fuse.

Owner Manual
Manual Kenmore Elite Microwave hood combo 72186013010

you require a new timer unit to be installed

That's a problem with the inverter or another high voltage part.

after removing the cover of microwave chk for continuty of cavity thermostat usually calld TCO(thermal cut off). it is located on top of the cavity and circular in shape.usually neutral wire goes through this 2 control board and this TCO is for protection of cavity from overheating.if this tco is open.then replace it.usually this happens when u cook for 2 long.

There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.

From the mini-manual:



(Note that these troubleshooting directions are meant for a technician, but one who swaps boards, not repairs them to component level)

To find helpful exploded view diagrams and get part numbers, you can just enter your full model number at the Sears parts site.

But Sears parts can usually be obtained for far less here by entering either the part number.

One should also check the wiring and connectors from the control board to the inverter and inverter to magnetron, etc.

Be sure to work with the power unplugged and you may want to discharge the high voltage capacitor.

If nothing else, you can save about $75 by taking it to the Sears-authorized shop yourself.

Otherwise, you can contact Sears for service.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

an inverter failure. This can sometimes by caused by a power surge or glitch through the electrical lines. You can sometimes clear this fault by completely unplugging the microwave for 1 minute. Plug it back in and see if the fault code returns. If it does, then you have an internal component failure that will need to be serviced by a technician. Microwaves must be serviced by technicians due to the inherent dangers involved in repairing these appliances. Internal capacitors can retain a lethal electrical charge even though the unit is completely unplugged. A microwave radiation leakage test must be performed on the unit following any internal component repair

Quoting another board:

Sears Kenmore Whirlpool LG 721.63683300. F-9 on this microwave IS inverter related.

There is a service tech troubleshooting document stuffed in behind the control board cover which has some testing procedures. My problem was the magnatron and checked out bad with the help of this document. It would run for a few seconds making clicks and then say F-9. It has been working great since I replaced the magnatron PN 6324w1a002c.

f9 model 721.63764300
Kenmore Elite 36 " over tne counter microwave is supplied by LG made by Gold Star, made in China. It's main problem is the high voltage inverter board supplyed by Sears Parts. If you get a F-9 code on your microwave display screen and the micro quits it's probably this board. Reset the machine by pulling the power plug and waiting an hour. If it is the high voltage board is at fault it will probably fail after 45 seconds of start up. This part is really hard to get at but is less than $100. A qualified technician should be able to remove and repair this item in less than hour. Some techs will quote you $300 labor, don't buy it, it should cost a $100 or less. No need to buy another microwave.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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?