LG microwave oven that does not heat up. LG MS-204H

This microwave oven was brought to my shop for repair and the problem was, it does not heat up. While the customer awaits in my shop, I did a small test. I put some water inside the microwave oven and tried to see if it heats the water or not. When turning on the oven, I could hear a loud noise coming from inside the microwave oven and it did not heat up the water.
From experience, when the microwave oven does not heat up, there is three possibilities:
1- The 220 volts is not reaching the main power transformer
2- The magnetron is shorted out
3- The .70 amp/5000 volts fuse between the 220 volts power transformer and the main capacitor is open causing the magnetron not to work due to the absence of power there.
By testing, I could read 220 volts reaching the main power transformer. The magnetron is not shorted out; This testing is done by testing the ohm reading between the metal body of the magnetron and the two terminals of the magnetron. If you get any reading between the terminals and the magnetron metal body, it is shorted and needed to be replaced. Usually the two terminals are connected together from the inside. It you test these two terminals with a continuity test setting, you will hear a beep. That is very normal.
I checked the fuse that is connecting the transformer to the main capacitor and it was open. this is a common problem in microwaves oven to find an open fuse there. Many repair technicians replace the fuse with higher amp rating causing the magnetron to blown or shorted it on the long run. It is very important to replace it with the same fuse specification to avoid any kind of problem in the microwave oven.
I replaced the fuse and turned the machine on. It worked and the water I put in the microwave oven started to get hot. One more problem remained; that is the loud noise of the oven. It was not suppose to have this loud noise. Usually, this is a problem with the main capacitor in the microwave and I think that is the main reason why the fuse was blown in the first place.
It is a very easy process to replace the capacitors but it is very important to make sure that the old capacitor in the microwave oven is discharged before replacing it. Even if the capacitor is bad, just make sure, it was discharged before replacing it with a new one. Upon replacing the old capacitor with a new one, the noise was gone.
The microwave ovens are very easy to fix and it can generated good income if you know how to do it. Just be careful when dealing with capacitors and magnetrons. Enjoy your repair and be safe.

Repairing Microwave Oven With No Heat Problem

Problem: No Heat.
Introduction:
Microwave ovens are found in every house hold. You can either cook or heat up food.  It comes in different sizes and models but all of them have one function, cook and heat. In my home town, especially in winter time, the electricity sometimes causes a lot of problem. Sometimes we lose electricity in the city. When the Electrical Company restores it, the power voltage shoots up to 280 before it is restored to the normal 220 volts. Due to this problem, a lot of electrical and electronic equipment break down in the house and cause them to malfunction.

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