• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake

FGMV174KFB Microwave won't heat

Dan O.

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Tomato, tomatto

The one on the picture that I had sent it says thermal cutout ...
Thermal cutout, thermo protector and thermal fuse are all synonyms for the same thing, a device that opens a circuit dependent on temperature. A "fuse" would usually describe a one-time device but the other descriptions could be used for a fuse as well. One terminology might be in the parts list while a different term used for the same item in a part catalog and even a different description for the same part in someone else's catalog.

They are different right?
The two parts are different, yes. At least different temperatures. One might be a one-time fuse while the other a resetable thermostat. I don't know for certain.


The one in my pic also has one on top plus a different one too?
I don't know what you're saying there. Sorry.


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Dan O.

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Where it is located?

What I was asking was if the cutout one that I sent you on the pic I took of my microwave
I don't know. I can't tell from the pic where that part is located. I said previously, "There are 2 in your model. One is mounted on the base of the microwave, the other above the oven cavity."

Which one is in the picture?

This square one with longer legs on this link what does it do?
The square one is also a thermal fuse. It looks to be mounted on or near the magnetron tube. The parts lists calls it "Microwave magnetron fuse".



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Dan O.

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Really?

.
Where on the microwave it is mounted???????

As I already said, I can't tell just by looking at the picture where it is. If you tell me if it is at the top of the oven cavity or on the base of the microwave, I'll tell you which one it is.
 

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It is at the bottom/base. No worries I understand you are trying to help and I apologize for the mess. I will first open up the plastic cover that is inside and take a look at the other fuses and see what is what. Maybe then I can get to work on this.
 

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Ok I just checked the one on top plus another one that's on top close to the magnetron and the base hood thermal cutout is bad as it won't beep. Everything else beeps.
 

Jacobariel

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That one should only affect operation of the hood fan.
Well it wasn't the thermostat like you said. I tested the magnetron with the lowest setting of 200 with the meter touching the terminals and read 0.03 then I did it again with 200 and this time one probe on one magnetron terminal and the other on the housing and read 1 or no movement. That means the magnetron is good to right?
 

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I never said that!

Jacobariel said:
Well it wasn't the thermostat like you said.
I never said that thermostat your problem was. In fact I said (and you even quoted!), "That one should only affect operation of the hood fan."


I tested the magnetron with the lowest setting of 200 with the meter touching the terminals and read 0.03
A reading of 0.03 when set on 200 (ohms) = 6 ohms (200 x 0.03). Usually that reading should be less an 1 ohm which with a meter set on 200 (ohms) would be less than 0.005 (eg. 0.004, 0.003, 0.002, 0.001, 0.0009, 0.0008, etc.)

then I did it again with 200 and this time one probe on one magnetron terminal and the other on the housing and read 1 or no movement.
That measurement is to be expected. It indicates the magnetron tube is not shorted to ground.


That means the magnetron is good to right?
I don't know about that. It does not seem to be measuring correctly but the determination of whether it is defective is up to whomever is doing the service. I'm not going to be blamed again for a misdiagnosis.


JMO

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Jacobariel

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I apologize I was not clear when I said it was not the thermostat like you said. What I was trying to say is that you are correct when you had told me that the thermostat only operates the hood fan. When you say the magnetron tube is not shorted to ground what does that mean? 1 or no movement is good?
 

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When you say the magnetron tube is not shorted to ground what does that mean?
It means that part has not failed in that particular way is all. There are a number of ways it can fail. It does not mean it is "good", just that it hasn't failed in that one way.

1 or no movement is good?
For that measurement, that reading is normal = not failed... in that way.

Dan O.
 

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Man this is frustrating trying to figure it out. The meter is great but it takes practice I guess on what to look for. I am almost ready to give up and buy a new one. Didn't want to spend $275 but it is what it is.

I may just buy a magnetron for $66 that I can return if that's not the part like the thermostat. I bought the thermostat simply because it didn't beep at the meter. If it is not the door switches, magnetron, diode, transformer then I don't know what else. If the capacitor is bad the unit won't even turn on right?
 

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How to check a microwave HV capacitor and diode

If the capacitor is bad the unit won't even turn on right?
No. Its failure would only effect the cooking system.

Rick previously posted a diagram of how to check the HV capacitor and diode on a microwave oven using a 9 volt battery. They can not be tested with regular meters, only higher-end ones with a 9 volt battery inside... or with the use of an external battery as illustrated.

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Jacobariel

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My meter has a 9v battery inside(to power the meter if that is the meter you are refereeing to). Can I use that and if so do I set it to the continuity setting like I've been doing?
 

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My meter has a 9v battery inside
Than it might be able to be used to test them.

do I set it to the continuity setting like I've been doing?
For testing the capacitor the instructions say to set the meter on 10K (which is resistance). The closest your meter has is 20K which should be fine. 2000 might also work just as well (which is 2K).

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Dan O.

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The 20k reads 0.00 and the 200k reads 1. or 0.00
If the meter is able to test it, when tested it should give a reading and slowly return to the default display. If you then reverse the leads and test again, the reading should be double then return to to the default display.

Also, I said 20k or 2000, not 200K (which is 200,000)

PS. please don't quote my whole message text in your response. It makes the posts necessarily long.

Dan O.
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Jacobariel

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I just tried it and goes from random numbers in the hundreds and back to 0. Changing polarity stays at 0.
 
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