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:
https://www.jestineyong.com/gt-sound-active-speaker-usb-port-not-working/
Mervin
January 29, 2016 at 4:20 pm
Nice fix and expertise.
Kees van de Wetering
January 29, 2016 at 5:47 pm
This is great. Thanks for the tip.
Elect.Eng
January 29, 2016 at 5:55 pm
Hello Suranga ,
Nice repair and thank you for this article ,
what is that small board that you added ?
what is called ?
Albert van Bemmelen
January 29, 2016 at 7:10 pm
Good job.
Yogesh Panchal
January 29, 2016 at 7:48 pm
Good job! Suranga.
Anouar
January 29, 2016 at 9:10 pm
Good job
Is that universal inverter ? What's you call that ?
Parasuraman S
January 29, 2016 at 9:12 pm
Good Job! A better alternative suggestion!
Robert Calk
January 29, 2016 at 9:12 pm
Good job, Suranga.
Luis Estrada
January 30, 2016 at 1:57 am
Nice! As we might say in my part of the world, your creativity is firing on all cylinders. Thank you for your inspiring us.
Suranga Electronics Sri Lanka
January 30, 2016 at 5:31 pm
Thanks..!! Your comment.
beh
January 30, 2016 at 12:28 pm
Hi Suranga
yes this is a good modification .but you did not told from where you received this another inventor board?
thanks
beh
Suranga Electronics Sri Lanka
January 30, 2016 at 5:34 pm
Thanks All of you...
Amir Mukhtar
February 3, 2016 at 1:08 pm
Thanks your Mr Suranga Bandara to Share your Repair Experiences with us.
Good Job and Keep Sharing to Learn Everyone from you.
thanks you Again
Amir Mukhtar Ashrafi
Karachi. PK
PRAKASH(VU3VPF)
January 30, 2016 at 6:01 pm
Hi Suranga good job
Zed
February 1, 2016 at 3:27 pm
nice repair info sir. but where this you get this inverter board ?
Humberto
February 2, 2016 at 1:08 pm
Good job. Congratulations and keep up.
steven neo
February 3, 2016 at 12:09 am
good job SURANGA .
this is one of the board on ebay. surf on the net you can find more ...
http://www.ebay.com/itm/New-Universal-CCFL-4-Lamp-Inverter-board-12-25V-larger-power-forLCD-screen-/170893679583?hash=item27ca0e9bdf:g:jdAAAOxyYYlRqHlE
Chris
June 16, 2016 at 5:48 am
Hi!
Nice and clean explanation.
I like your creativity in your articles.
Keep on!
My best regards.
allanGEE
February 24, 2017 at 10:58 pm
Good explanation! What are the parts on the board with the high voltage stickers on them?
george
October 31, 2018 at 10:35 pm
hi how did you modify the inverter board,cause i cant see what you did
Nico Douglas
January 29, 2019 at 9:40 pm
hi i have also converted a 32" hisense to led, i have a problem to disable the inverter circuit so that i can still use the original powersupply.The powersupply and inverter is combined on one board,is there a way to do this. I think it goes into protection mode when there is no ccfl installed.