ACO1860AC LG Range - Instructions

Over the stove microwave installed in top cabinet row.
1. Unplug device.
2. Two people to remove from wall/cabinet (remove two, large, top mounting screws and rotate entire microwave down and off the wall mount). Should be some wood spacers between top of device and bottom of cabinet.
3. Remove screws from sheet metal cover.
4. Remove one screw holding blowers in place and rotate out of the way, in order to gain access to 2 of 5 screws that hold the magnetron in place.
5. Unplug magnetron and remove the 5 screws.
6. Drop in new magnetron and re-assemble microwave in reverse order (steps 5-3).
7. Two people restore micro to wall/cabinet. Replace wood spacers, re-install two, large mounting screws (finger-tight). Test device. Secure the two large screws.

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.

This site was very helpful with locating this part. Shipping was fast. Thanks!

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.

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 verified I had 120 volts going into transformer when the microwave was supposed to be running. The capacitor and HV diode both tested good. Be sure to discharge the capacitor before working in this area. This isolated trouble to either the transformer or magnetron. The windings of the transformer measured good. So ordered a magnetron. It was very easy to swap. There were 4 screws and one connector. This fixed our 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.

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!

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 .

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.

very simple

Replaced with new covers.

I unscrewed the light cover, removed the burned out light bulb and replaced it with one I ordered on Partselect.com. It was very easy.

Lifted up the glass plate and stuck the assembly under it ;)