PLMB186KC - Instructions

First I had to accept the fact that the unit was designed to keep non-professional people from doing any repairs. The switch was installed in such a manner that I had to break the mounting to remove the switch, then drill a hole in the mounting to secure the new switch in place.

tested cap. with ohm meter which showed a short. A new HV cap., a fuse and it is working fine again.

With this model, you must remove the outer covering. Don't try to access the display unit from the front like I've seen in some other GE microwave videos. After removing the outer covering, the switches are easy to replace. They are very visible and easy to get to without taking any other parts off. You will see the door switches just behind the display board. Remove the switch and then remove the connecting wires to ensure you don't inadvertently brake a wire. You will need a tamper resistant star bit to remove 3 or 4 screws from the back panel. All other screws are philips head. I went ahead and replaced both switches (yes...there are two of them) and works like a charm. I saved an $800 microwave for less than $60 and know what to do if it happens again. Appears to be a common problem on this model. Thanks for others making a post...It saved me time and money reading others remarks. Good luck!

It was so easy to order a new glass plate ! Love this web site,

Part just snapped into place and wires were reattached.

Unscrewed the control panel (2 screws), lift up and let hang, with a plan screwdriver open bracket holding the switch, unplug 2 wires, replace with new switch, plug in the 2 wires, push switch back into bracket. Then slide on the control panel, put the 2 screws back. Easy fix.

i unplugged the unit,unscrewed the outer shell so that all the wiring and internal components were visible.starting at the first of three micro switches i removed the slip on terminals installed the alligator clips too the wires so the switch would now be bypassed.i made sure the wires and clips were not touching anything plugged unit in and it worked.i then installed the new switch and closed up the outer shell

Replaced the 16" tray with a 14" tray. Works great now. Took about 20 seconds to take out the old tray and put in the new.

I first read where someone had the same problem. Their solution was a burned-out fuse. I ordered a new fuse...installed it and that did not solve my problem. I revisted PartSelect and read how Marla (from Arlington, TX)solved her problem. I purchased a secondary switch and when it arrived, I made a copy of Marla's instructions and followed them to the letter. I installed the new secondary switch into the secondary space, put everything back together and the oven STILL DID NOT WORK. I had to take the latching panel apart again and test each switch to see if there was another bad one. I found that the third switch was burned out. So I took the new switch out of the second slot and installed it into the third slot. I tested the switches before reinstalling the latching panel. This time everything worked. So I put everything back together, reinstalled the microwave on the wall, tested it again, and everything worked perfectly.

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.

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.

Replaced the fuse. Result; did not fix the problem.

Replace the fuses

Unit was painted inside recently, but apparently some paint fumes still lingered so that when the unit was turn on, there was a very small explosion that took out the flam sensor thermostat. This thermostat interrupts the white leg of the AC input and cuts off all power.Performing a continuity test on the flame sensor showed it was permanently open (no continuity). Turns out I had a similar part from an old coffee maker and when I installed this part, the microwave turned on just fine. So I order the correct sensor from Parts Select. Part installation involved removing the TT20 Security Star bits (4) and the right/left side phillips screws. Now the top/side unit cover comes off by pulling the cover backwards and up and out. The flame sensor is in the middle of the front section underneath the top cover, and comes out easily with pull-off connectors. There are also bendable pins that hold the sensor down flush to the top of the unit.

I pulled out the unit and found 2 interlock switches that are depressed when the door closes. After cycling the door open/closed I found that one of the switches occasionally would stay depressed. The repair was easy (after I took off the panels so I could get to the switch) I simply removed 2 screws that attached the interlock switch assemblies to the main unit. Then I popped out the defective switch and popped in the new one. This did indeed fix my problem.