Still Have Hope In A Faulty Switch Mode Power Supply
This Macksonic 32 inch LED TV came in for repair with the complaint of lightning struck. The customer asked me do my best to repair it because it was a gift by someone. The below photo is the power supply and mainboard (two in one) that built in together.
First, it looks complicated but as you take your time to see it properly, you can actually see the power supply section at the left side and the mainboard section is at the right side.
The next thing I did was to check on the main fuse and the bridge rectifier and both the components were bad. See the photo below:
I’m not sure how did the customer knew about his TV was struck by lightning, so I proceeded to check on the power FET and power IC. With Ohm test both components were having short circuit
As I went along to check other components in the power side, I stumbled a slight burnt SMD resistor. Even the Optoisolator IC was bad too!
There seems to be so many components that had problem and it was not easy for me to place order for the power FET and the power IC because it will take sometimes to reach my country.
The fastest way and the only choice I have was to do a modification by using the module below:
I can’t document everything in this article as it will take lots of pages to explain how I have successfully modified it. If you really need to learn how the modification can be done then check out on Jestine Yong’s ebook here on power supply modification. This ebook worth the investment because with one successful modification on the power supply for your customer, you will get back the investment.
In this power supply modification you really need to know where to tap on the points in the primary power section. Below are the photos taken after I had done the modification:
Conclusion- If you can find parts or you have ready parts then there is no need for the modification. If you can’t locate the part, missing part number or even someone took out the components then the only choice you have is to modify the power supply. I had actually done few of this modifications and it was quite reliable. In times to come I will share to you another power supply repair with this kind of modification. Ok, will see you again in the next article.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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