Question about Whirlpool GH4155XP Microwave Oven

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Microwave ahs power but doesn't heat.

I have an older model (RM278BXV) Whirlpool microwave that matches the oven. I don't want to replace it if there's a fix. Everything runs on the microwave, but it doesn't heat at all. Any idea if there's an easy fix? I think Sears keeps parts for 20 years on their stuff (Whirlpool). Thanx!

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The most common causes for a lack of heating are a bad door switch, a loose connection on the magnetron, a bad magnetron, bad connection on the control circuit board, a bad relay on the board, bad high voltage diode, or bad high voltage transformer. If you or a friend decide to work on it, we have *critical* safety, disassembly, and troubleshooting info at our site, which is linked at our listing here on FixYa: You can find helpful exploded view diagrams and order parts by entering your model number here:

Posted on Sep 28, 2007

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Check the magnetron and related circuit and high voltage fuse and high voltage diodes, etc..

Posted on Sep 25, 2007


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Diode The high voltage diode converts the A/C power output of the transformer to D/C, doubling the voltage to nearly 5,000 volts. This high voltage powers the magnetron which emits the energy that cooks the food. If the diode burns out, a lower A/C voltage reaches the magnetron, which is not sufficient to power the magnetron. When the diode fails it is often visibly burned out. If it appears to be good, it can be tested with a volt-Ohm meter capable of testing diodes. High voltage diodes frequently fail and are one of the most common points of failure in a microwave oven.

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Have an older model (RM278BXV) Whirlpool microwave

what is the problem with it im guessing it prob doesnt heat, if so prob need to get acess inside and check components i would recommend getting a service call as some componoents inside are still live even when unplugged,, it might require a magnetron which would be fairly expensive but if u dont wana replace it than i guess its your only option.. hope this helps

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