Kevin C. for Model Number JES1456WJ05 My thermal cutoff tripped a couple months ago. I ordered a new one, and while replacing the tripped one, I noticed some of the plastic insulation on the connector for the black wire coming from the transformer to the TCO was distorted/melted a little. I figured it had something to do with the TCO cutting out, so I just continued putting things back together. I attached the wires to the new TCO, reassembled everything, and life was good for about 2 weeks. I smelled something burning while running the microwave to heat some water. I unplugged, removed the outer skin, and the plastic insulation on the connector on the same black wire from the transformer had melted/charred. (But the TCO did not cut out). I cut the fried connector off, put on a new connector, reassembled everything. Lasted 2 days. More burning plastic. The new connector is shot. Why is the connector melting? Is the transformer sending too much voltage through it? Is there a test I can do with a multimeter to test the transformer? Thanks
Answer Hello Kevin, This is caused by excessive current flow. You should test the components for possible shorting to ground. If you find nothing shorting to ground, (partial short because a dead short would open the ceramic fuse), replace the high voltage capacitor WB27X10280 and the high voltage diode WB27X10597. As a note, the thermal cut out will not open from excessive current flow unless it heats it up since a thermal fuse is only opened by excessive temperatures. Read More... Answered by AppliancePartsPros.com | Friday, January 16, 2015