Microwave runs for 3 seconds and shuts off

if smells like something then something is burning stop using answer about can it be fixed is unknown till diagnosed

There could be food or oil buildup around the door frame which will absorb some of the radiant and microwave energy whilst cooking. Give it all a good clean and see if that helps. If everything else is working properly, it may be a problem with the cooling fan. Microwave ovens have a "stirrer fan" inside the roof or rear of the cooking area to disperse the microwaves and some convection / microwave ovens also have a cooling fan which assists in dissipating heat within the cabinet.

If microwave runs only without turn table, I am suggest to check if turntable electric motor has got short circuit. If yes, I have some left.

Step 1:

Door Switch

If the microwave runs for a few seconds and then shuts off, a door switch might have failed intermittently. Check each of the door switches for any signs of overheating, arcing, or burning. Also check each of them for continuity. Replace any of the switches that is visibly damaged or that only has continuity intermittently

Step 2:

Main Control Board

If the microwave runs for a few seconds and stops there may be a short circuit in the main control board. Check other components first, these boards are often misdiagnosed.

Touchpad and Control Panel

If the microwave runs for a few seconds and stops the touchpad and control panel might be defective. There are several other components that can cause this problem, be sure to check any other components before replacing this board.

Touchpad

If the microwave runs for a few seconds and stops the touchpad might be at fault. This is not common. Generally speaking, if the microwave display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad.

High Voltage Transformer

If the microwave runs for a few seconds and stops the high voltage transformer might have an intermittent short. This is not common. Check other components related to the microwave symptom first.

Thermostat

If the microwave runs for a few seconds and stops the thermostat might be defective. Watch our video on testing thermostat

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Step 6:

use the DVOM tester and fix it. God bless you

Hello


Power Supply

Check whether there is a proper power supply. Look to see whether the cord is connected to a grounded 3-prong outlet and the cord is fully plugged in. If the electrical system is built-in and no power cord is visible, replace or reset the household fuse or circuit breaker.

Microwave Functions

Some basic microwave operational steps may affect whether the microwave is heating. Open and close the microwave door, as the unit will not function with the door open, and push "Stop/Clear" to cancel any previous settings, such as the timer, which do not heat the microwave oven.

Setting the Microwave

Once the power to the microwave has been reset, or verified as working, and the microwave is ready to run, select a new cook cycle and press "Start" to see if the microwave begins to run and cook food as expected. Allow the food to cook for the alloted time and then open the microwave door and check to see if the food has cooked or heated. Choose a longer cooking time and restart the microwave if food is heating but is cooking slowly.

Repair

If all efforts to troubleshoot the function and power to the microwave still do not get the appliance heating food as expected, there may be a repair issue that needs to be addressed. Contact professional technician for advice.

Tom, It sounds like either your magnetron and door switch have gone out or the control board. From your description, I would think that it is combination of the door switch and magnetron, which are expensive to replace - are you sure you want to put that type of money into a 9 year old unit.

http://www.searspartsdirect.com/partsdirect/part-number/Frigidaire-Parts/Microwave-Parts/5304408930/0022/628/Model-CPLMV168CC1/1428/0123370?keySuffixId=NA&productTypeId=0123370&searchModelNumber=CPLMV168CC1&subCompDesc=Functional%20parts&brandDesc=FRIGIDAIRE&modelDesc=MICROWAVE&blt=11

And the door switch parts are even higher.

If a Goldstar, LG or Zenith MV1610 or MV1608 is running but not seeming to heat a load placed in center of turntable, its probably because the "stirrer" intended to spread microwaves generated by the magnetron around the cook chamber is stuck so that most all the heating is directed toward the back and top rather than the center of the cook chamber. This usually occurs after cooking for longer than a minute with no load in the cook chamber - as when a model w/o a timer (such as a MV1608) is intentionally operated in cook mode to serve as a kitchen timer, or when a model with a timer function (such a MV1610) is accidentally operated for longer than a minute w/o any load. Before assuming the magnetron (usually warranted for 5, 8 or even 10 years) or other high voltage component such as diode or capacitor needs to be replaced, try “cooking” a 16 oz pyrex cup of water at full power on the outer edge of the turntable for 2-3 minutes - which usually reactivates the "stirrer" and restores normal cooking function.

Magnetron and diode most likely. Need more info.

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

Hi try unplugging form mains for an hour this will reset any settings back to factory settings let me know what happens after doing this then i can assist you further ok