MS85MN (HBLEGSS) LG Range - Instructions

Pop old one out and replaced it with new one.

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.

Problem was a faulty door latch switch. I easily accessed the switch by removing the control panel, total of 4 screws. After that, just disconnected the three switch door latch assembly and connected the new one. Took about half an hour and was very easy. Unit works perfectly now.

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.