MT3130SHB - Instructions

I want to preface this review by stating that I do some DIY from YouTube, but have no experience in electronic repair. The microwave is over the stove with the extendavent. First I unplugged the microwave, removed the vent and started to unscrew the microwave from the mount. I used a power drill to speed things up. I was able to remove the microwave on my own. I unscrewed the lid on the microwave and took the lid off and there is the magnetron. I opened up needle nose pliers to have each end touch the terminals of the capacitor (holds the power, Dangerous). I made sure to keep my hands on the rubber handles and avoid touching the metal part of the pliers. I used the pliers to remove the plug of the capacitor to the magnetron as well. The magnetron has 4 screws (2 top, 2 bottom). There is a magnet that can hold the screws to keep from falling but I’d still recommend a screwdriver with a magnet on the end. The magnetron has another set of wires connected by a metal bracket like a holder, not really connecting any wiring to the magnetron itself. I had to unscrew 1 screw to removed that. Adding everything back on was easy, same steps back. I plugged in the microwave and tested a cup of water before I mounted it back above the stove. Voila! I did need my wife’s help to hold the microwave on the hinge while screwing into the mount. It doesn’t take a lot of muscle for the help. $85 for the part and ~40 mins to fix a $400 microwave!

Used a Motor cycle Jack to remove both unites combined. Removed side panels exposing internal working parts. Removed nonworking Magnetron and replaced it with new Magnetron. The process was completed in about 1 hour.

Removed door from microwave and then popped the inside widow trim ring off. Removed 4 screws from the window bracket, replaced the latch with a new part and then assembled.

Problem was due to a faulty door switch. Replaced with a new switch and the microwave now works fine! Only thing that was tricky was that LG uses the hex screws with a peg in the middle to keep the microwave cover on. Had to use a small screwdriver and pliers (on the screwdriver) to unscrew the screws.

took out plastic piece under plate (that was broken) and placed new one in the hole. No tools req'd. Works like new.

I UNPLUGGED the microwave and removed the cover, using a phillips and a Torx screwdriver for the machine screws. I set these screws aside, so as not to confuse them with the later encountered screws. I photographed the magnetron to assure proper placement of the 6 phillips machine screws involved in reassembly (marking the the locations on the old magnetron would do as well. I marked the old magnetron "old", to avoid later confusion. I removed the two screws holding the shields to the magnetron. I removed 3 of the 4 screws holding the magnetron to the microwave, leaving one of the top screws. I held the magnetron securely and removed the last screw, pulling out a the part of the magnetron that penetrated the microwave. I installed the new magnetron in reverse order. One problem I encountered was locating one of the six screws, which had been pulled into the old magnetron by magnetism.

Initial failure of over range microwave Aug 3rd. Control Panel worked but no heat. Took to local LG authoriaed local repair place. They fixed it quickly and we re-installed it. Worked fine for 2 months then had similar failure again. Agaim took to same authorized repairer. They kept unit for 3 months but finally concluded theu could not fix it and suggested we contact LG for a partial refund. When they tested the unit during re-assembly in my presence, there was a blue flash and the fuse blew. Since we had built a custom tile mural back splash around this unit, I brought it home, ordered a number of time delay fuses new capacitor and two new high voltage diodes. However, using my Fluke DMM, I checked the existing capacitor and high voltage diode and they checked OK so I just replaced the time delay fuse. The high voltage transformer leads had 2 possible ways to connect to capacitor and diode. Tried one way, plugged unit in and turned it on, and immediatly blew the fuse. Replaced the fuse and reversed the high voltage transformer connections,amd turned unit pn, and it worked perfectly. Since we had experienced several power failures during the time of the original failure, the repairer concluded that power spikes might be at fault, so I also purchased a TrippLite ISOBAR4ULTRA 3300 Joule surge protector between wall outlet and microwave, and re-installed over range. It has worked perfectly since.

unplug the unit then pull down , lot of screws are on top. open the cover . you could see the parts that need to replace on the right hand side (heavy side). disconnect wires then test the parts that need to replace by a tester to make sure that it's really broke .then unscrew part and replace .

Ice covered the top back of the freezer compartment. This did not allow the cold air to move up to the fridge. Complete defrosting (36hrs) fixed the problem. There was a lot of water, from ice inside, that was not visible. We realized the freezer drawer must have been left cracked open. Thanks so much.

Ordered the switches from Partselect, arrive in two days. Had trouble removing the plastic connectors from the old switch terminals, one of the plastic protectors broke, but was able to reuse it. It took a little figuring out how to remove the existing switches. Must push in a tab and rotate the switch on a little pin, then remove. Must be careful not to break the plastic tabs holding the switches in place. Replaced all (3) switches at the same time. All in all it was pretty easy.

I called to make sure I was replacing the correct part. I paid over the phone and it came the next day. Very very easy process.

Partselect sent me the right thing in two days! The whole process was easy as pie.

Replaced the diode (aka wire-vltge) in the HV circuit after removing cabinet cover using both the secure torx screw drvr & phillips head screw drvr. The hardest part of the job was finding the secure torx nut drvr tool on the internet & purchasing same.

I started by calling a reputable service company to diagnose my problem. The repair tech told me it was the magnetron and it was a "very difficult" repair that required two people because the over-the-range unit needed to be taken down. I asked for a detailed estimate. He quoted $550 including parts and labor. After he left, I researched the part costs on this site and realized his costs were very inflated. I purchased the magnetron for $220. It arrived at my door two days later. Installation was very easy. First, I unplugged the unit. Then, while my wife was making sure it did not fall off the wall bracket, I unscrewed the two mounting screws from the top of the cabinet. I lifted the unit down from the wall and set it on the kitchen counter. The shell needed removed from the microwave which involved about 20 screws. This provided access to the magnetron on top. The magnetron is secured by five screws and a plug. I unplugged it, unscrewed it, and removed the old part. Then, I installed the new magnetron, and tested the microwave to make sure this did the trick. It worked. I put the outer shell back on the microwave and cleaned the microwave. (This is a great opportunity to clean the areas you do not typically see!). I then remounted the unit and plugged it back in. Saved myself a bit of money so I took the family out to dinner and a movie to celebrate. Microwave was in working order for heating up left overs the next day! Thank you!!!

Since others reported similar problems and it was just the fuse we tried that first. That wasn't the problem so we ordered the Door Interlock Switch Kit. Shipping was very fast! Our microwave had 3 switches. My husband asked how to know which one to switch. I read that one person just did process of elimination. Luckily ours worked on the first change out! So happy to have stumbled across this site and not have to buy a whole new microwave.