In my limited experience magnetron failure is common but testing is not easy or safe.
Anyone reasonably competent can check that mains power is feeding the primary of the big transformer but unless you have eht test equipment and some training your testing should stop there and hand it over to an accredited repairer.
The voltage and current on the high voltage side of the transformer is potentially lethal and far exceeds the capacity of equipment available to the handyman..
SOURCE: no heat
If you can't fel the cooling fan blowing air out the back, then that increases the chance you have a bad magnetron. Since this is 1-1/2 months old, it is still under warranty. I would call GE or Sears for warranty service. If you break any seals opening it up, you'll void the warranty. It's almost certainly not the capacitor, those virtually always short when they fail, resulting in a blown fuse. If the transformer's bad, there is often the smell of electrical burning, but the cooling fan may weaken the smell. Try smelling the fan exhaust after it has run. It's most likely the magnetron, from my experience, but it could be a shorted HV diode. Some GE models sem to have had a batch of bad magnetrons, but I don't know if they have publicly acknowledged that. Again, since it's under warranty, the best bet is to call the manufacturer or an authorized GE servicer. You can find those numbers in your owner's manual and need to have your sales receipt handy of course when you call. Good luck.
SOURCE: Frigidaire Microwave OTR FMV145KS2 not heating
Chances are it's a defective high voltage rectifier diode or magnetron.
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.
At
our Web site, we have a video
available showing how to remove a typical
over the range control panel assembly in under 5 minutes.
Here are some links you
or someone you know can use for test help, but read their safety
warnings first:
http://www.gallawa.com/microtech/diode.html
(if it's not shorted or burned, it's
probably okay)
http://www.gallawa.com/microtech/mag_test.html
http://www.gallawa.com/microtech/xformer.html
http://www.gallawa.com/microtech/cap_test.html
You can find
helpful exploded view diagrams and order parts by entering your full
model number from the tag on the oven here.
You can
download Frigidaire owner's manuals and installation
instructions can be downloaded through the links here. where you can also locate a nearby authorized servicer if you choose.
The magnetron has a 10-year part warranty, but you would have to pay labor.
If
nothing else, you can save about $75 by taking it to the shop yourself.
Good luck.
We're happy
to help you with free advice and we'd appreciate your thoughtful rating
of our answer.
SOURCE: Maytag MMV5156AAS Microwave won't heat and has hum/buzz.
A failed diode isn't the most common failure, but it happens. And sometimes it's due to bad magnetron or a bad connection.
If the capacitor fails, it almost always shorts, which results in a blown fuse whenever you hit "Start" to run the microwave.
The magnetron on this model should have a 5-year warranty, in case that's relevant. Your owner's manual is here.
We have
the service / repair manual for this model and have uploaded it to our
site here to help you.
It will give you safety info, step by step help in disassembly, troubleshooting tips, and part numbers.
Here are some links you
or someone you know can use for test help, but read their safety
warnings first:
http://www.gallawa.com/microtech/diode.html
(if it's not shorted or burned, it's
probably okay)
http://www.gallawa.com/microtech/mag_test.html
http://www.gallawa.com/microtech/xformer.html
http://www.gallawa.com/microtech/cap_test.html
There
should also 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.
At
our Web site, we have a video
available showing how to remove a typical
over the range control panel assembly in under 5 minutes.
You can find
helpful exploded view diagrams and order parts here.
We're
happy to help you with free advice and we'd appreciate your
thoughtful rating of our answer.
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. 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.
If
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.
If
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.
If
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
If
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
If
the microwave doesn't heat the thermal fuse may have blown. It can
be tested for continuity. Watch our fuse testing video for more
information.
If
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.
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. 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.
If
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.
If
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.
If
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
If
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
If
the microwave doesn't heat the thermal fuse may have blown. It can
be tested for continuity. Watch our fuse testing video for more
information.
If
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.
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