How To Repair No Power Symptom In LED TV
This Polytron LED TV came in with the complaint of no power. I retested the TV by connecting the AC input and yes indeed it was no power. After the removal of the TV cover I saw three circuit boards.
The circuit boards are the power supply board, main board and the T-con board-see the photo below:
Since the complaint was no power so the first thing to check was the main fuse. From visual inspection it was very clear that the main fuse was severely blown-see the white arrow in the photo below. This indicated a direct short circuit in component that had caused a large current drawn that had blown the fuse.
I proceeded to check on the bridge rectifier and found all the four diodes were shorted.
Next, I checked on the main power FET and it was shorted too- see the two photos below:
Further testing of components corresponding to the power FET did not yield any bad components. I then replaced the bad components with new one (except the main fuse) and soldered a light bulb across the fuse holder to check and make sure no more shorted components. The power LED lighted up and I knew now I can put in the main fuse and power On.
The result was a perfect picture -see the photo below:
Conclusion- It was a quite straight forward solution and if you would like to troubleshoot and repair power supplies like a professional I suggest that you check out Jestine Yong’s ebook HERE.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments. If you have electronic repair articles to share with us, please contact us HERE.
P.S- If you enjoyed reading the above article, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!
Note: You may check out his previous post in the below links: