A friend of mine called me to pass by his place to check out on his 22 inch LED TV.
I passed by and after powering the television I noticed that the power ON led was ON but RED in color.
The TV has no power On switch and therefore once power is applied from the outlet the Tv would go into standby mode waiting for the power on button to be pressed from the remote control or front keys.
After pressing the power on button from the remote control I noticed the power ON led was not changing from red to green and therefore decided to open up the set.
After opening the set I went straight to the main board and started scanning the board and I noticed a burnt area near the inverter connector as you can see below.
I also noted that there was some components which was burnt beyond recognition.
Checking from the board marking I was able to conclude that it was a transistor (QP4)
Since I could not get the same board on time to check out the exact reference of this transistor and I could not tell which other components is gone assuming that transistor hardly fail alone (there must be cause I decided to order for an universal controller driver board.)
I ordered the board and after receiving it I noted it has no user manual whatsoever and therefore being the first time I had challenges.
The first challenge was that the board came with on screen language set to Chinese.
I struggled a bit and was able to get the menu in English language and this was a big boost to the installation process.
Usually the kit comes with all connection cables which include the keyboard and IR and a remote control but no inverter and therefore I used the old one.
So I removed the old board and installed the new one, before applying the power you need to be careful to see the connection is done rightly otherwise you may apply power and damage the board instantly.
First be sure the connection are done correctly, when connecting the keyboard and IR connector be sure to start inserting the cable from the left corner and leave a small space on your right hand side as you can see below.
LVDS cable connections guidelines.
Usually pin 1 of the LVDS cable is marked on the board, so is the connector and therefore you should be careful otherwise you will damage your board instantly if you reverse the connector.
Usually the board do not come with heat sink installed on the main I.C. I noted in my case the I.C was getting quite hot and therefore I salvaged one from the old board.
Setting the screen (panel) voltage.
Usually these board have jumpers on board for setting panel voltage like 3.3 volts, 5 volts and 12 volts depending on the panel requirement you are replacing.
To know the board requirement you need to access the panel and find out where the panel model number is marked as shown below
Once you get the panel number you can then google it out for find out the specifications.
Below you can the specification for this panel LM190E08 and I was able to confirm it require a supply voltage of 5 volts. With this information I set the screen voltage to 5volts using the onboard jumper.
On-board jumper for setting panel voltage.
After several attempt and making several mistake, I was happy with the final results and so was the owner this TV without a brand name (Just LED TV).
Here are some ebooks on lcd/led repair which i recommend to you, for more info click here.
Thanks you guys
see you in the next class