Microwave oven Repair with clicking On/off symptoms. Model LG
A customer brought his microwave oven for repair. It was not a heating issue but it was something strange that I have not seen it happen in any microwave oven. It was a challenge so let get started.
The moment I powered up the device, it shows that is on but the moment I open the door, I could hear a relay clicking and the light in the microwave oven goes on and off. If I continue with the heating process, it would heat fine but the clicking noise and light going on and off bothered the customer.
I took the cover off and first thing to do was to discharge the main voltage capacitor. After doing that safely and nicely, I proceed with the repair.
There are two relays on the door control panel and the first thing to do is finding which one is doing the clicking. I located the relay that was clicking and started to check things around it. I took the relay out and tested and it checked fine.
As I was checking around the relay I came across some bad capacitors that are rated 100uf/16 volts. I did that with my ESR meter while the capacitors still on board. I took them off board and tested them again. Check this out.
If you look at the photo, you will see the lower arrow showing what should be the ESR reading for the capacitor but the upper arrows showed the actual ESR of the capacitor and both of these capacitors were faulty.
Once these capacitors were replaced and tested the microwave oven, the clicking was gone and the light was steady the moment I open the microwave door.
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.
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Note: You can check his previous repair articles in the link below:
https://www.electronicsrepairfaq.com/shorted-igbt-on-a-welding-machine-replaced
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Jestine Yong works as an Electronics Repair Lecturer in Kuala Lumpur Malaysia and his training website is http://www.NoahtechElectronicsTraining.com. You can check out his repair blog at http://www.JestineYong.com
21 comments on “Microwave oven Repair with clicking On/off symptoms. Model LG”
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Excellent! A very rare repair on a microwave oven! Good information! Thanks for sharing!
Parasuraman: thank you. you are most welcome. have a blessed day
What part on the control board would keep the exhaust fan not turning off, the sensors and door switches all check ok, thanks John
Straigthforward pro job! Clicking relays can indeed be most distracting!
Albert: thanks man. have a blessed day
Nice job, Waleed
Andrew: thanks man. enjoy your day.
Great job Walleed thanks a lot.
Justice: you are most welcome. have an amazing day
Hey Waleed,
I find microwave ovens fascinating to work on. Well done on your repair!
Mark: thanks man. I love to work on them as well. have a blessed day.
Hi my Samsung led tv red light is on constantly and pressing on button but does nothing. I checked power supply I’m getting 5v and 12v going to main board.when I pull out connector from ps to the main board the back lights come on. What could be the issue. Thanks
Devan: are you getting the 3.2 volts on the power board? check it when the tv is not coming on. that is normal to get 5 volts because that is the stand by voltage. when you pull the connector out, while the TV is on or Off? I had the same problem with LG tv. all voltages are ok but the tv is not on. the moment i check the LED light with the LED tester, the LED light comes on. my problem was with the LED light themselves. first check all the capacitors on the power supply with ESR tester then check into the LED lights as well. best of luck
Great information enjoy your holiday
BASHEER KHAN
Basheer: you are most welcome.
Good Job! Waleed
Yogesh: thanks. and have a blessed day
Waleed,that is good work. I am learning a lot from your posts.Thank you so much.
What if the microwave is blowing fuses after a short cook(heating up)?what could be the possible fault.
secondly I came across another fault, which is similar to the one above but the fuse could blow upon closing of the oven door.
Hi Waleed how do you discharge the main voltage capacitor?
Thanks for a great post.
Regards
good afternoon!thanks for the info on the microwave ovev pcb caps. i was able to repair two ovens with similar clickng relay sound.
thanks a million times!!!