ACM1580AS - Instructions

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).

Pulled unit out, pried the bottom plate off the unit. Mine was not screwed in, but designed to be pried off, and then replaced. That was a surprise, but not very difficult. Unscrewed the motor, unplugged the electric connection, replaced it with new part . Replaced the bottom plate and tested the machine.

Access is via RT. SIDE Panel as you face microwave. There are three screws on the bottom right edge to loosen. After that the side panel slips down and off. the fuse is located in the rear near where the power cord comes in. It is the white ceramic tube 1/4" in dia. and 1-1/2" long. Pull it out like any fuse and replace with new one. Reassemble and you are done!

ordered a new tray

1. Order correct light bulb for unit and have it with you before removing old lightbulb.
My Microwave is built into cabinet.
2. Disconnect power (Either turn breaker off or unplug unit from wall)
3. Remove face cover on cabinet. (4 Phillips head screws)
I was able to reach in the opening in the cabinet and unplug from the wall.
4. Remove Phillip head screws holding microwave in cabinet.
5. Remove microwave from cabinet.
6. Remove Phillip head screws and torx screws holding outside cover on the back of unit and the side (1 on right side) and then remove cover.
Light bulb is on the top front right side.
7. Remove 1 philip head screw holding light bulb and unplug quick connector wires.
8. Plug quick connector into new light bulb same way it came out and place new light bulb in place and put the 1 philips head screw holding it back in place.
9. Put cover back on and all the screws. Temporary plug the unit in to test light bulb works before securing it back into cabinet.
10. Reverse order 5,4,Plug unit in wall before putting the face back on.
Done.

Did an online search for repairs and found PartSelect. Simple to order the part and had it installed myself less than a week later. Thank you!!

Watched a you tube video prior to installing new switch. Followed the video which gave me confidence i was up to the task. After removing the touch pad I found my design was not exactly like the you tube model but I found the defective switch, replaced it and put the microwave back together. Works great. Again watch the videos

remove the shroud. 2 types of screws. Philips and 2 specialty star screws. Then remove the light socket. 1 Philips screw. replace the socket and bulb. The bulb and socket are 1 piece. Replace the shroud.

Required that i remove the built in frame and mounting. Required tamper proof socket to remove housing. I removed the old bulb and simply replaced and reverse installed the cabinet.

Replace (after testing w/ohm meter) diode and locker holder. My door often would not close properly. Microwave let know by saying not shut properly. When disassembled found the top screw mount was hollowed out resulting in it moving on occasion when you close door. First remove casing (special safety torx head) needed for rear screws. Onc e removed all parts available to view or work on. Diode is on the capacitor so caution is needed when removing. Serious shock hazard if touched. Use insulated pliers to remove from capacitor and a phillips on the ground. Test with ohm meter Should have resistance on way and non the opposite. Replaced mine bad. Next the holder 2 phillips screws and its yours. Unplug each switch and remove. Take note to what wires go to what switch and what switch mounts where. Mine had 3 switches. Removed from old holder and put in new. Screwed holder back in place and left scrws loose till re wired. Once wired set the holder by lightly tighting the screws. Try the door till it seats properly ensuring that all 3 switches are working properly. If so thighten screws. If all seems to work as advertised, safely plug in and test unit if heats up un plug and put cover back on micro. Your all set. Happy heating.

You Tube

I looked up my problem on the internet and found a very helpful video. Microwave on video was different brand but the internals and methods were very much the same. The video made it simple and easy to fix. Found the replacement switch on the LG parts site and ordered. Two different switch types. One with red switch, the other green. Part was $7.28. Saved a bundle in service costs. Here is the repair video.

https://www.youtube.com/watch?reload=9&v=_AglBJoHgDs

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.

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.

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.