MMV4205AAS - Instructions

Over a period of a year or so, our over the stove microwaive oven started sounding like a thrashing machine every time we turned it on and got progressivly worse. The repair service wanted nearly half the cost of the appliance to just come out to take a look. I removed the oven from the wall cabinet, removed the cover and discovered that the cooling fan blade had come loose from the motor shaft and was hitting the casing. I ordered the fan motor assembly from you folks, replaced the faulty fan, and the problem was resolved at about one half of the cost of a service call.

It was great to find the part I needed. I did'nt have a model number because the microwave was in the cabinetry. Yet I was still able to find just what I neede thanks to the photos.No store had it but parts select did. thanks!

I unplugged the microwave. I did watch a YouTube video to see how the plastic frame around the door could be removed. I used a putty knife to pry it off. The spring was still in good shape, so I hooked it up to the new latch/locker part and onto the microwave. This was just a little time consuming because I was trying to be careful so I wouldn't break anything on the new part. The plastic frame clicked right back on. I plugged the microwave in and it worked right away. If I can do it, you can do it. Sure beat buying a new microwave. Great experience.

Removed case,
Discharged HV capacitor and removed cooling fan.
Unscrewed ground end of HV diode and unplugged from HV capacitor.
Installed new diode by reversing the order. In my case, the problem was the magnetron was bad, so I replaced it as well.

Lifted out old support put new one in. Fixed in less than 30 sec.

Read the troubleshooting section on this site. Figured it was an interlock problem because the food was not getting hot (magentron not turning on) and the carousel was not turning. Did not think both the carousel motor and magnetron failed at same time, thus indicated an interlock problem. The interlock switches are actuated by the door latch. Replaced the assembly locker piece with all three switches (only a $20 dollar part) and microwave was fully operational again. Wife and kids think I am a hero.

change light bulbs

Initially we started looking to buy a replacement microwave to replace our 13+ year old built-in microwave. It was a real pain finding a replacement to fit the exact dimensions. So I thought I'd try to find an old KitchenAid microwave. However, I was pleasantly surprised when this site came up on my search. Their website allows me to input the problems and then it showed two possible parts that needed to be replaced. I emailed tech support and asked them which part I needed. They responded very quickly and said I needed to replace the magnetron. I watched a couple YouTube videos and then pulled my microwave apart. It was incredibly easy to pull the outer cover off. The magnetron had 5 screws that needed to be removed and one electrical plug. Took me maybe 10 min to complete the entire repair. It was one of the easiest repairs I've done and so thankful for this site They saved me a ton of money from not buying a new microwave and we now have our microwave working again. In hindsight, I wouldn't hesitate. I'd order the Part now and get it fixed.

I followed an old appliance repair forums post from 2008 that discussed this exact common issue with this LG model. It took me quite a while to find the info. Then I used the schematic diagrams on your website to find where the part was located inside the microwave. I removed the outer cover. I tested all components including the thermostat for continuity with a multimeter. I discovered there wasn't any continuity in the thermostat so ordered the part and replaced it. Everything works like a charm! Thanks for the great, fast service.

I thought that if I went one more time to visit my son, and the microwave tray was still gone (due to their having broken it), I would just order the part MYSELF!! So, that is what I had to do. They have been without this for at least 3-4 months........ Well, it was sitting at my door in less than 48 hours after I ordered it! Easy, easy, easy..........thank you!

Unplug the microwave. Remove the Philips head and safety Torx head screws along the bottom of the sides and rear of the microwave which hold the black cover on. Lift the cover up at the rear and slide it backwards to disengage the tabs on the front top. Remove the cover. Discharge the capacitor by shorting the terminals to each other and then ground. Do this with a well insulated object and be aware there may be a pop when you do this. Keep hands, etc. on the insulated part of the object (screwdriver handle, etc). There's a lot of stored energy in that capacitor. I'd advise first checking the diode to make sure its not bad. Replace it if it is. The Magnatron is held in with a couple of screws on the top and sides. Unplug the connector and remove the screws. Remove the Magnatron. Installation is the reverse of removal.

Took microwave out of builtin cabinet with 4 screws.
Put microwave on center island and removed cover.
Tested interlock switch with volt meter and it appeared ok so I put my kit back in box and sent back.
Took out magnetron unit and replace with new part.
Put cover back on and test.
All is working and installed back in cabinet. Two weeks later all still working great.

removed a dozen screws-discarded large cap-replaced diode-replaced a dozen screws(took longer to replace them than remove for some unknown reason). Microwave now works(wife happy).

After checking all three switches for continuity I determined that the plastic door lever had warped or gone out of wack. After shutting off power at the breaker box I removed the door, the inside trim piece around the inside of the glass. Removed the black two prong door lever, reattached the new door lever and then reinstalled the trim piece and all screws. Works fine now. Easy fix just make sure your switches are all ok then replace the door lever.

I had to unmount the over-the-range microwave oven to be able to gain access to the interior of the oven. Complicating removal (and re-installation) was the fact that there is a "pot-filler" faucet installed directly underneath the oven. In retrospect, I should've removed the faucet before doing the repair, but "c'est la vie."

After I got the microwave down, removing the case was also "interesting." I get bonus points for the fact that the previous owner must've had to replace the same diode before - and then re-assembled the microwave case incorrectly - thereby adding to the confusion (BTW, the service manual that I found online said nothing about how to remove the oven's case).

To remove the case, undo all the screws holding it on, and then rotate the case upwards from the back while also pulling the case backwards. There are crimped folds on the inside of the case that mate with the back edges of the front of the oven's chassis, and these folds have to be unclipped from the chassis in order to remove the case.

Replacing the diode itself was the easiest part of the job. The two connectors on the diode are of different types, making it impossible to install the diode with the wrong polarity.

BTW, the diode that had failed was not an OEM diode; I suspect it was a generic component that had been installed by a repairman sometime between 2004-2008 (when our home's original owners still owned the home). On the other hand, the new diode from PartSelect is an OEM part (it came packaged in a sealed Whirlpool bag).

The fact that the oven had stopped heating indicated that it was either the high-voltage diode or the magnetron that had failed. Since a replacement diode costs ~ 1/10th as much as a replacement magnetron, I figured it made sense to replace the cheaper part first. Fortunately, this fixed the problem.

One last thing: I tried testing both the old and new diodes for conductivity and polarity using my volt-ohm meter (VOM), but I was unable to get either diode to "turn on," even though my VOM is powered by a 9-v battery, and I used the 2-Mohm range setting. I guess the test voltage of my el-cheapo VOM isn't high enough to exceed the diode's threshold voltage, (even though I have successfully used this same VOM to test low-voltage diodes).