16.33 V 5.47V X 2 Linear Transformer fault
Customer sent to me this Singer SWD800EL23 Model Microwave Oven for repair with the complaint of no power symptom. Obviously the first component to check is the Main fuse.
I had to open the front cover panel in order to access the internal section. Take a look at the two photos below:
Once the front cover was removed, I could see the high voltage transformer and the main fuse was tested good. This indicated there was no serious short circuit otherwise the main fuse could have open circuited.
To cut the story short, I checked on the linear transformer (not high voltage transformer) which was located in the power supply/mainboard. There was no output AC voltage from the transformer when tested with my AC voltmeter.
I further tested the transformer primary winding off board and found it to be open circuited (no resistance value)- see the photo below:
Since I do not have this ready part, I searched from the internet and managed to find one. The brand name is Galanz which is also famous for manufacturing Magnetron.
Once the new transformer is fixed and powered on, I could see that the power was fine by looking at the panel display:
So in order to check if it is fully working we have to test the microwave oven by putting a cup of water and heat it. The result was good and I concluded that it was fixed and no further test is required.
Conclusion- Microwave oven just like any other electronic equipment where you need to know how the equipment functions before you start to repair it. If you want to learn how to check and test the linear transformer, main fuse and many other electronic components, you can check out Jestine’s ebook here.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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https://jestineyong.com/never-expect-just-one-component-is-defective/
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Azaria
August 14, 2018 at 12:48 pm
Good work master
Justice (City of Durban --South Africa)
August 14, 2018 at 1:04 pm
I do a lot of microwave repair but never came across this fault. Thank you for this interesting article ,was so curious to follow your logical repair steps.
Albert van Bemmelen
August 14, 2018 at 2:35 pm
Interesting and good explained repair. The microwave oven in this article has at least a decent long living display. Most microwave displays have gas tube displays like in the old VCR recorders that deteriorate in time and are harder to read after years of service. And replacing those is almost impossible because of the display symbol differences between the many manufacturers of microwave ovens.
suranaga Electronics
August 14, 2018 at 7:11 pm
Yes,
Thank you Mr.Albert.
Parasuraman
August 14, 2018 at 3:48 pm
Excellent information shared! Thanks!
Robert Calk Jr.
August 14, 2018 at 4:07 pm
Good job, Suranga.
Yogesh Panchal
August 15, 2018 at 12:32 am
Good Job! Suranga
Mihai
August 15, 2018 at 12:57 am
Thanks for sharing your experience !
Ali rıza
August 15, 2018 at 4:28 am
Thank you.repair man.
Turkey.
Haren Barsaikia
August 15, 2018 at 5:46 pm
Very nice, good job done.
Thanks for sharing.
Humberto
August 16, 2018 at 12:16 am
Good job Suranga, as usual. I really enjoy reading your articles.
Ulises Aguilar
August 16, 2018 at 11:27 am
good job Sir
Henrique Jorge Guimarães Ulbrich
August 19, 2018 at 11:14 pm
Great and fast, Suranga. As the other works you´ve performed. As Mr. Justice said above, it´s not common problems with transformers.
ulises Aguilar pazzani
August 5, 2019 at 11:27 am
Good job Mr Bandara