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.
By the way if you have any good repair article that you want me to publish in this blog please do contact me HERE.
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beh
September 28, 2013 at 2:04 am
HI WALEED
thank you so much of this article but my question is ? how much you paid for this new magnetron .by my experience the price of a new magnetron more or less is equal to a new microwave oven?
thanks in advance for your answer
beh
Waleed Rishmawi
September 29, 2013 at 9:12 pm
Hi Beh. I have plenty of them in my shop. they are not brand new ones. the new ones are very expensive to get. I know of a place that sells old microwave ovens and buy a lot of them for really cheap price. then I take them apart and use them for my repair. keep in mind that I tell the customer that the magnetron are used not new.
eliazer
September 28, 2013 at 4:49 am
hi my mr yong im a newbby and i love electronics repair.and your pdf books they really are helpfull like the smps. and how to test electronics components like a profesional. and i allways come to your site and read the articles you always post thank u for that.
i have a question i read the article on No power in a microwave oven repaired. Model:ITT M7017PA
and my question is bides the mark on the board it ware missing two
47 ohm 5 watts resistors. how did find out the value
Jestine Yong
September 28, 2013 at 10:35 am
HI Eliazer,
Thanks and I will leave to Waleed to answer that question since he is the one that had repaired the oven.
Jestine
Richard
September 29, 2013 at 12:26 am
Thanks for the tips. I really enjoy them.
Waleed Rishmawi
September 29, 2013 at 9:22 pm
Eliazer: yes, good question. usually the power board for the microwave ovens are not marked. but I know the value of these resistors from experience. these resitors usally have their value printed on them and I have came across alot of open bad resistor butt value was still printed on them. I hope this answers your question. I have plenty of these power boards in my shop that I get from used microwave ovens. they help me to get the cost down and keep the custoner happy with the service I am providing. I also tell the customer that I am using second hands parts and they are ok with it as long the microwave ovens work and the price of the repair is low.
Robert
September 28, 2013 at 8:09 am
Thanks for the tips, Waleed.
Andre Gopee
September 29, 2013 at 1:31 am
I myself would like to know how did he find out the value and wattage of the resistor. I can see from the photo where the resistor are missing and the markings, but not the value.
Andre
Waleed Rishmawi
September 29, 2013 at 9:23 pm
please read the comment i sent to Eliazer..he had the same question. God bless you
Espoir
September 30, 2013 at 3:59 am
Than kyou for that repair tips.
bob lou
October 2, 2013 at 3:28 am
Good work...we stopped fixing them years ago because of the high cost of parts. And it's good to see an honest repair person, you tell the customer that the part is used, but they are happy to have their oven working again.
Waleed Rishmawi
October 2, 2013 at 2:53 pm
thanks bob. the best thing is to be honest with the customer and when he is happy, he comes back for more.