GE JVM1440 Spacesaver Microwave

You can fix it without the aid of a repairman. Simply unplug the microwave and remove the outer casing. There should be a few screws around the bottom edge and back panel. Once you have the unit open, look for where the power cord comes in. There should be a circuit board with a fuse mounted to it. This is your input line filter. The fuse should be a 20 amp appliance fuse that you can pick up at any hardware store (Lowe's and Home Depot both carry them). DO NOT op test with the outer casing removed. Potentials of about 14,000 volts are present in the high voltage network of a microwave oven. Close the unit up BEFORE you power it back up. Let me know if this helps.

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This may have already been dealt with, but others can benefit from an accurate, thoughtful reply to this problem.

This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.

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By the way, modern microwave ovens here in the US don't have an "input line filter", and the high voltage output is only 3-4000 volts DC, not 14,000 volts. It's still quite lethal, but I like to be accurate. Helps the old credibility, eh? Older black and white CRT-type TVs used 10,0000 volts and color models used 25,000 volts. Maybe this is what caused the previous confusion? Be safe!