KCMS185JSS - Instructions

The power on the microwave went completely out when I went to use it, but there was no power failure for the house or neighborhood. We removed the microwave from above the oven. Took out the screws on the sides and back of the microwave and slid the top back. The line fuse was located on top unobstructed, NOT behind the button panel like some microwave models. As the appliance is over 20 years old the line fuse was quite old. It was really hard to pry it out of its holder and actually broke. I used a vacuum to suck up the dust and glass and it was easier to get out the ends once the middle broke. Popped the new line fuse in, slid the top back on, put in the screws and put the microwave back in its compartment above the stove. Good as new!! We were about to spend money on a new microwave, but thankfully I came across this site. So happy I did!!

This repair was really easy. The part that took the most time was taking it down from it's compartment above the oven and putting it back up there once repaired.

Removed some cosmetic panels. Removed the assembly with micro switches. Examined the faulty switch by checking the clicking action of switch. Two others were ok by this method. Replaced the switch with new one. Works fine so far. Thanks to web site and YouTube videos.

Turned the microwave on its side. (Recommend turning it on its top. i had to fish the wire connection back to the center after it dropped away from the motor.) There is a spot under the rotation motor where an access port was stamped in the tin but not cut out. Used the small side cutter to complete the cut where tin had been left between holes. I unplugged the wires, removed the old motor by removing one screw, and installed the new one by reusing the same screw. The motor must have a reduction gear inside the case. The motor coil tested good, about 128 ohms, but it acted like there was a stripped gear inside. I wasn't interested enough to try to open the motor and confirm.

Had to go to the garage and get a small sheet metal screw to close the new trap door.

The "new" motor had scratches on it, made me wonder if it was really new, but it works fine and will probably outlast me.

Take cover off microwave. Check door switches to determine which one was faulty.Remove and replace faulty switch.

Using fingers, the old turntable roller guide was pulled up off the motor shaft. The plastic roller guide shaft coupler was found to be broken, allowing the motor shaft to spin without turning the roller guide. The hole in the floor of the oven was inspected, and no broken pieces were found which could interfere with the new roller guide. The new roller guide was then gently pressed down over the motor shaft. Very easy.

It seems that the heat of the microwave cracks the part over time. It is a very simple installation.

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 from cabinetry, take cover off and had a very difficult time removing the plastic form that has the switched in. Replace the lowest of all the switches, and then again very difficult time getting the plastic form back in. Some of the plastic even broke during the process but not any that could prevent it from working as it did before. I had ordered a fuse, 2 packs of 2 switches as there are 3 switches but only had to use 1 to get it working again. Tested after switch install, put the cover back on and reinstalled in the cabinet.

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!

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

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 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

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.

Easy, and the microwave still doesn't work.