Question about GE Microwave Ovens
If it goes dead almost
immediately after pressing the Start pad, that's usually a shorted
If it goes dead several seconds after pressing the Start pad, that's usually a failing high-voltage transformer.
Here are some links you or someone you know can use for test help, but read their safety warnings first:
(if bad, it will be shorted)
There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.
You can find helpful exploded view diagrams and order parts by entering your full model number from the tag on the oven here.
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Posted on Jul 19, 2009
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Posted on Jan 02, 2017
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Jul 28, 2013 | Microwave Ovens
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. A regular meter with a
diode checker will not work to check these diodes. You have to use a
meter with a 9 volt battery or put a 9 volt battery in series with
the diode to check it.
the microwave does not heat, one of the door switches might be
defective. Microwave ovens normally have three door switches, if any
of them fail the microwave does not turn on and does not heat. Check
the switches for continuity with an Ohm meter.
the microwave oven doesn't heat the magnetron tube might have burned
out. The magnetron uses high voltage, high current DC power to
generate the microwave frequency that cooks the food. If the
microwave oven is turned on when it is empty this can cause the
magnetron to burn out. Once it is burned out it has to be replaced,
it's not repairable.
the microwave doesn't heat the high voltage capacitor might be
defective. The high voltage capacitor works with the high voltage
diode to convert the output of the transformer to DC voltage and to
double the output voltage. If the capacitor is burned out the entire
high voltage circuit stops working properly. The high voltage
capacitor can be checked with a special VOM meter which has a
capacitance testing capability. Be aware that the high voltage
capacitor can retain a charge of more than 3,000 volts and can
injure or kill a person if not handled properly. Only trained
technicians should perform this type of testin
the microwave does not heat, the high voltage transformer might be
burned out. Microwave ovens produce a very high voltage in order to
power the magnetron antenna, which emits the energy that cooks the
food. When a high voltage transformer fails it will usually arch and
have a burning smell
the microwave doesn't heat the thermoprotector may have tripped. This
is a safety device to prevent the microwave from overheating. It can
be tested for continuity to see if it's blown.
Feb 07, 2013 | Microwave Ovens
Aug 19, 2017 | Whirlpool MH1160XS Convection/Microwave...
causes are an open thermal protector or thermal fuse but could also be blown
fuse in HV area of microwave (somewhat uncommon in domestic microwaves).
Less likely causes are failure of other parts in the HV area.
If the main power fuse is located in the primary of the high voltage
transformer rather then at the line input, the clock and touchpad will work but
the fuse will blow upon initiating a cook cycle. Or, if the fuse has already
blown there will simply be no heating action once the cook cycle is started.
There are other variations depending on whether the cooling fan, oven light,
and so forth are located down stream of the fuse.
Some models may have a separate high voltage fuse. If this is blown,
there will be no heating but no other symptoms. However, high voltage fuses are
somewhat rare on domestic ovens.
A number of failures can result in the fuse NOT blowing but still no
A shorted HV diode, magnetron, or certain parts of the HV wiring would
probably result in a loud hum from the HV transformer but will likely not blow
the main fuse. (However, the HV fuse - not present on most domestic ovens -
Depending on design, a number of other component failures could result in no heat as well including a defective relay or triac, interlock switch(s), and controller.
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