After researching the most probable causes, I purchased the top two likely parts (the main fuse & thermistors/thermostat). After reviewing several videos of generic over the range (OTR) microwave ovens, I attempted to remove the requisite parts to gain access to the fuse (only after unplugging the m/w oven from the wall outlet!). I tested the old fuse for continuity using my multimeter (sound is good, no sound is not good) and confirmed it was bad. I checked the replacement fuse, just to make sure it was good before installing it, in the same manner. It was good. The access was not as advertised and the directions on the LG website were not helpful. After some maneuvering, I replaced the fuse, along with the parts I had previously removed. I then plugged the cord back into the wall outlet and everything is working! With some patience and a $5.00 fuse, I saved $200.00 by doing it myself (and didn’t break anything or injure myself in the process). Not too shabby.