No power in a microwave oven repaired. Model: ITT M7017PA
A guy living in Jerusalem brought this Microwave oven to my shop and told me that it does not power up.
The moment I powered up the machine I could not see any indication of a working microwave oven. I checked the fuse, it was open. Something shorted the fuse out and caused some problem in this machine. Let us begin.
Do you see anything missing in the power board? Two resistors were supposed to be in that marked space. I saw that the moment I took the cover off. They were two 47 ohm 5 watts resistors. There were missing and there was no sign of any black burn or anything. Usually there are signs of burn marks because these resistors go bad very often. My only explanation to this is the owner of the microwave oven took it to someone to fix it. He found the burnt resistors and fuse replaced and still the machine did not work.
I am thinking that this problem is deeper than just burnt resistors and open fuse. I was willing to explore and see what can be done to bring this microwave oven back to life.
The moment I replaced the two resistors and put a light bulb in the fuse holder and powered up the machine, it did not show any kind of short in the machine which was a very good sign.
I put everything back together and powered up the machine. The light came on, the fuse stayed intact but it was not heating. There was voltage reading at the main power transformer and the only thing was left to do is to change the microwave magnetron.
I am sure you have seen this before. This is the microwave magnetron that produces heat once it gets enough power. Without this, the microwave oven is not an oven. I found this piece to be faulty and it had to be replaced. Make sure you discharge the main capacitor before you replace it otherwise, you will get shocked even if the microwave oven was not plugged in power.
Once I replaced this one as well, and powered up the machine. I heated a cup of water and the microwave oven worked like a charm. Mission accomplished.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment. Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
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