20 Most Recent Whirlpool MH1170XS Microwave Oven Questions & Answers

You will need to replace the cooling fan motor. Remove it and check the numbers on the fan and then do an online search for the motor. you can also contact a website called the repairclinic.

Yes it has a fuse. Take the cover off and the fuse is on the right hand side, behind the control panel

Sometimes you get lucky with just changing the fuse, the most cost effective way to fix a microwave oven.

If the microwave oven is the newer type [7years or less], the problem is most likely the magnetron or the inverter board, but if model is older check for a shorted high voltage capacitor.

This an early indicator that the magnetron "heats the food" is failing, usually they will go without warning and eventually will need to be replaced.

Sounds like the waveguide cover has been contaminated with food that has carbonised and burning.
Call a Whirlpool repair agent and get the waveguide cover replaced.
They need to be kept clean and leaving the door open after cooking helps to dry the moisture out in the cavity. Making it last longer.

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.

YOUR SAFETY IS PARAMOUNT

This is a job for a professional but if you are safety clued up, here's instruction.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 or moving coil meter on high resistance range for short circuit, (DVM's won't show the fault!), the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.

Fuse is usually located behind the control panel. Most likely 20 amp. If your m/w has a top grille it will have to be removed. Look for a screw in the top of the control panel. Panel has tabs to hold it to body, lift up to release panel. A word of warning... m/w ovens have potentially lethal high voltage present even when the unit is unplugged. If you are not familiar with high voltage circuits, then this is not a job for a DIYer.

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 on high resistance range for short circuit, the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.