First at all, I'm not professional in electronics, just using some simple trick to light up CCFL back light in old TV.
To success, make sure your CCFL tubes and driver still okay, the TV control board are not using in this case (so no reuse of remote control for the light)
The project include handling high voltage, be careful.
Step 1: Taking the TV Apart Until You See the CCFL Panel
I think all of you have no problem in taking the TV apart, remove all screws until you see the CCFL tubes.
In my case there are 2 PCB board inside the TV, one for the power supply (include CCFL driver). The other is for controlling the TV itself, since it's broken in my case so I just threw it into my PCBs collection box.
You need to see which board the CCFL panel directly connected to, you need that board.
Step 2: Testing the Driver
Connect the CCFL panel back to its driver and then connect the driver to your home socket. I think CCFL use AC so just connect the wires back is okay.
Switch on your power and if the CCFL light up, and you are done. Just remove the LCD panel and the mount the back light back into your TV case (if still in one piece).
If it's not lighting up, you face the same case with me. Go to the next step.
Step 3: Testing the Circuit and Find Out the "switch"
I manage to find the output for the power supply panel to the other PCB.
There are 12 connections.
First I try measuring the +24V output to see whether there's any voltage. In my case, there is just a little bit voltage, so I consider there is other switch for controlling the output for this 24V.
Then I found the P_ON output (I guess is panel on?), I try connect some resistor (10k,1k,and direct connect), from +24V to the P_ON. Nothing happen. And I tried connect to the BL_ON (backlight on), still nothing happened.
After remove the main power supply and wait for few minutes to let the capacitor discharge. I flip the PCB and start tracing where the power input goes.
I found a relay is located very near to the power inlet and controlling the live wire at the beginning. There's some other path where the live wire go but after that is too complicated. The relay is not triggered when I turn on the power. So I decided to power up the relay 1st.
The relay rated 12V for the coil, so I just use the Lead Acid battery that very near from my hand (bad idea), direct connect it to test the relay. And one of the diod blew up, at lease the relay is okay and the +24V was successfully measured.
Step 4: Turning on the CCFL Panel
After I got the +24V output, I try putting some 10k resistor to the BL_ON and then turning the relay on with my battery, and the CCFL panel finally light up!
So I just remove the relay and then short a wire into it, making the path close.
Now the CCFL panel light up when I connect the plug into the socket. That make life easier and I got an extra relay :)
Basically that's all for this project, the next step just some extra things I found in the process
Step 5: Others
When taking apart the TV, it smell like vinegar, I think it's from some degraded plastic?
The plastic inside the panel are became very fragile.
I think I will make a wooden frame for it and connect all metal parts to ground wires (This TV has no ground wire in its circuit)
I am quite scare the PCB will burst into flame since I bypass some of the circuit, can some expert tell me is this okay :)