Most Popular Way To Modify LCD TV Inverter Board
The complaint of this Olan LCD TV was no power so I had to remove the cover in order to perform the troubleshooting job.
Once the cover was removed I could see 3 circuit boards i.e; the power board, the mainboard and the inverter boards-see the photo below:
The first board to check was the power supply board. However, the fuse and other major components were checked to be in good condition. I powered up the power supply and check on the output voltages in the mainboard and inverter connectors. It reads zero volt, so this means either the power supply itself has problem or something shorted in the mainboard or inverter board that causes zero volt.
I decided to remove the inverter board connector first and see how it goes.
I was actually surprised to see that once the connector was removed the LCD TV power LED lighted up!
So this means the inverter board was shorted causing the power supply not to work. I set my mutlitmeter to diode scale measure between the 12 v dc supply pin and the cold ground pin and the result was shorted-see the photo below:
I started to trace from the 12 volt dc line and eventually when I removed the high voltage transformer the short circuit immediately went away. This confirms that one of the high voltage transformer pin was shorted to ground.
Since I can’t find the exact part, I used a much simpler way which is to modify a 4 Lamps external inverter board. You must know what you are doing because there were 4 wires in this external inverter board. Each wire has it owns function such as the VCC, Ground, Adj, On/Off. For your information, this is one of the most popular ways to modify LCD TV inverter board when you can’t find the parts to replace in the original board. Besides, it is much faster and saving your precious repair time.
Once done the modification, I had to look for a suitable place to secure the inverter board. Since this board is small, it was not a problem to fix it on the TV-see the photo below:
The LCD TV came back to life when I applied the power. Another job done and made some profits.
This article was prepared for you by Suranga Bandara who owns an Electronics shop in Anuradapura, Sri Lanka.
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Note: You may check out his previous repair article in the below link: