Thread: Microwave fuse keeps blowing

Hi,

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When I pressed start it sounded like normal and seemed ok, but after about 1 sec there were 3 or 4 clunking sounds then it stopped working and went dead. The fuse had blown again.

More often than not, a shorted high voltage capacitor.

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I took the capacitor with me to Jaycar when I got some more fuses. They tested it for me and said it was within tolerance.

Check it again.

http://www.applianceaid.com/micro4.html

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From what I have read, it doesn't sond like it is the Magnetron and I haven't tested the diode as I am not sure how to.

Usually the mag or diode won't blow the fuse, they may growl or make a strange noise and stop heating but normally don't blow the fuse.

Testing...
http://www.applianceaid.com/component.html

If needed:


Capacitor, hv Manufacturer Number A60905500AP

jeff.

Quote:

Check it again. http://www.applianceaid.com/micro4.html

Thanks Jeff,

I have pulled the capacitor out of the microwave again and have tried to test with my digital m/meter. Have followed the instuction on your link, however have a couple of questions.

1st up, the instructions suggest setting on Rx1. My m/meter has 20M, 200k, 20k, 2000, 200 settings. Internet research says that Rx1 is equivalent to 200. Is that correct?

2nd, the testing instructions say to "touch the cap terminals ( red lead on left and black lead on right )" Excuse my ignornace, but that is a bit confusing for me. 'doh! As I look at the capacitor as it would be positioned in place in the microwave, there are 2 caps. The left side has 3 terminals and the right hand side has 1. When I connect the red m/meter lead to any 1 of the 3 terminals on the left cap and the black lead to the terminal on the right cap, the reading stays on 1 and doesn't change at all. When I reverse the red and black leads, the reading again stays on 1.

I am not sure if I am testing the capacitor correctly or whether the capacitor needs to be replaced. BTW, the capacitor is not out of shape or bloated and there are no signs of any oil.


Hoping someone can help with the next steps. Thanks.

I have pulled the capacitor out of the microwave again and have tried to test with my digital m/meter

Needle meter is used...especially for microwave stuff...that's all we use.

the capacitor is not out of shape or bloated and there are no signs of any oil.

Normally wouldn't be.

Internet research says that Rx1 is equivalent to 200. Is that correct?

Not really.

When I connect the red m/meter lead to any 1 of the 3 terminals on the left cap and the black lead to the terminal on the right cap, the reading stays on 1 and doesn't change at all. When I reverse the red and black leads, the reading again stays on 1.

What does your meter say when you put the two meter leads together?

jeff.

Needle meter is used...especially for microwave stuff...that's all we use.

thanks Jeff, I only have the digital version.


Normally wouldn't be.



Not really.



What does your meter say when you put the two meter leads together?

When I put the leads together, it reads 00.4 or 00.5


thanks Jeff

Ian

See if this helps:

Originally Posted by rickgburton

See if this helps:

Thanks for making it simple for me Rick.

Set the m/meter to 2000
Touched tthe probes together and reading was 000
Then put one probe on A and other on B - reading did not change at all and continued to show 1
Swapped probes and again reading did not change and continued to show 1

Do you think that means the capacitor needs replacing?

If the meter didn't change, replace it. Use the link jeff1 gave you.

What does your meter say when you put the two meter leads together?

When I put the leads together, it reads 00.4 or 00.5

Which is wrong, should read 0.

Then put one probe on A and other on B - reading did not change at all and continued to show 1
Swapped probes and again reading did not change and continued to show 1

For what ever reason it is showing open....only thing to do is swap out the capacitor and forget the meter testing.

jeff.

Originally Posted by rickgburton

If the meter didn't change, replace it. Use the link jeff1 gave you.

Thanks for your help Rick and Jeff. Will replace the capacitor and let you know how it goes.

cheers