F1961W - Instructions

The instructions on the website were incredibly easy and I saved myself a lot of headache by using this site.

-it was built in unit - so I needed to pull the decorative grill from around the outside to remove it from the wall
- removing the back of the case involved removing phillips head screws from along the side and back of the unit. the only issue I encountered on removing screws was the fact that the "torx / star" screws could not be fit with the wrench that I had (they had a pin in the center that would not allow the wrench to fit into the star). However, a pair of pliers was handy and they were removed just easily.
- I had ordered both the high voltage diode and magnetron because I didn't know which item was the problem. I grounded the diode with two screwdrivers while wearing rubber gloves to be safe. the warnings on this did the trick as it was the only scary part of the operation.
- the diode was a little hard to spot looking at the schematics, but is is found on the lower right corner of the right side of the panel and easily pulled out and replaced. I tried the microwave again to see if it worked...and it did not. So I confirmed that the magnetron was the issue.
- removing the screws for the magnetron and putting in the replacement was a dead easy and I tried the microwave again before putting cover back on. Worked like a charm. Super easy!

I had to unmount the over-the-range microwave oven to be able to gain access to the interior of the oven. Complicating removal (and re-installation) was the fact that there is a "pot-filler" faucet installed directly underneath the oven. In retrospect, I should've removed the faucet before doing the repair, but "c'est la vie."

After I got the microwave down, removing the case was also "interesting." I get bonus points for the fact that the previous owner must've had to replace the same diode before - and then re-assembled the microwave case incorrectly - thereby adding to the confusion (BTW, the service manual that I found online said nothing about how to remove the oven's case).

To remove the case, undo all the screws holding it on, and then rotate the case upwards from the back while also pulling the case backwards. There are crimped folds on the inside of the case that mate with the back edges of the front of the oven's chassis, and these folds have to be unclipped from the chassis in order to remove the case.

Replacing the diode itself was the easiest part of the job. The two connectors on the diode are of different types, making it impossible to install the diode with the wrong polarity.

BTW, the diode that had failed was not an OEM diode; I suspect it was a generic component that had been installed by a repairman sometime between 2004-2008 (when our home's original owners still owned the home). On the other hand, the new diode from PartSelect is an OEM part (it came packaged in a sealed Whirlpool bag).

The fact that the oven had stopped heating indicated that it was either the high-voltage diode or the magnetron that had failed. Since a replacement diode costs ~ 1/10th as much as a replacement magnetron, I figured it made sense to replace the cheaper part first. Fortunately, this fixed the problem.

One last thing: I tried testing both the old and new diodes for conductivity and polarity using my volt-ohm meter (VOM), but I was unable to get either diode to "turn on," even though my VOM is powered by a 9-v battery, and I used the 2-Mohm range setting. I guess the test voltage of my el-cheapo VOM isn't high enough to exceed the diode's threshold voltage, (even though I have successfully used this same VOM to test low-voltage diodes).

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.

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.

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).

Took microwave out of builtin cabinet with 4 screws.
Put microwave on center island and removed cover.
Tested interlock switch with volt meter and it appeared ok so I put my kit back in box and sent back.
Took out magnetron unit and replace with new part.
Put cover back on and test.
All is working and installed back in cabinet. Two weeks later all still working great.

I went to LG website enter model number and was given a list of parts that need to be replaced with a percentage of which part fails the most. I order micro switch PS3522738 which arrived and PS3529293 was backordered. I installed the one that arrived. The microwave worked briefly. I reordered and waited for both switches to arrive and installed both. The microwave still doesn't work.

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

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.

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.

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

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

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 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 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.