Question about GE JVM1440 Microwave Oven
The power on my microwave JVM1340WW002 started to go down after few seconds into operation (~5 sec not right away) and then shut down completely. Found that fuse was blown. After replacing the fuse it would shut down as soon as it would start, blowing the fuse again. The High power Capacitor and rectifier show no visible sign of damage. Checked door switch and thermal sensors (two of them - both fine: one is normally open). It leaves either HV Capacitor/Diode, Transformer or Magnetron (still under warranty). I would be inclined to suspect the Capacitor, but the fact that microwave was able to start and died down in few seconds raises doubts. My understanding is that HV cap is there to provide the boost on start up only. Please help.
Generally speaking, if the high voltage capacitor is shorted, the fuse will blow as soon as you hit the START pad. When the HV cap fails, I've never seen one do anything but short. If it's a few seconds or so into cooking, it's usually the high-voltage transformer. There may or may not be a burning smell. The cooling fan often will dissipate the smell. What can happen to the transformer is an expansion of the windings to the point where a couple of hot spots eventually make bare spots which touch, then the short causes the fuse to blow. When it cools, they aren't shorting anymore. It's possible it's the mag or something else, but not too likely. You can (carefully!) disconnect the primary leads from the HV transformer then run the oven, making sure the wires are free and clear. If the fuse blows, the problem is in the low-voltage side. If it doesn't the trouble is in the HV side. If you broke a seal (tamper tag) or left any other evidence that you were inside the microwave, your warranty will be voided. Some parts may be covered, but the labor warranty usually expires sooner. Be careful.
Posted on Nov 07, 2006
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If it blows the fuse as soon as you hit the START button, it's almost certainly a shorted high-voltage capacitor.
If it blows a few seconds after you hit the START button, it's probably the high-voltage transformer. You'll possibly also smell a faint electrical burning smell from the rear vent after you shut if off.
Microwave can be very dangerous so it is best to have it looked by a professional
Would appreciate a solved rating for expert advise.
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