This guide published by www.laptopsockets.co.uk explains how you can replaced the CCFL tube a.k.a. backlight lamp inside the LCD screen removed from a Sony laptop.

WARNING! This guide is only for experienced technicians. The CCFL tube is located INSIDE the LCD screen. In order to replace the CCFL tube you’ll have to remove and disassemble the LCD screen. You can damage the screen during the disassembly process.

Backlight failure symptoms:

1. Your laptop starts with a reddish tint on the screen and after a while the image returns to normal. Most likely this is CCFL tube failure.
2. White color on the screen has a red tone. After a while the backlight turns off. You still can see the image on the screen, but it’s very faint. Most likely this is CCFL tube failure.
3. The backlight randomly turns on and off without any pattern. This could be inverter failure or CCFL tube failure.
4. Your laptop starts without backlight. Everything works fine with an external monitor, but the image on the laptop screen is barely visible. This could be inverter failure or CCFL tube failure.
5. Your laptop starts without backlight. You can light up the screen for a while if you tap on the lid close switch. This could be inverter failure or CCFL tube failure.

Possible solutions:

From my experience, screen inverters fail more often then CCFL tubes.
If you have symptoms 1 and 2, most likely your problem is related to the CCFL tube.
If you have symptoms 3-5, I would try replacing the inverter board first and move to the CCFL tube only if replacing the inverter didn’t fix the problem.

Let me say it again. Replacing the CCFL tube is only for experienced technicians. For all other people I would suggest replacing the whole LCD screen.

You’ll find more backlight troubleshooting and repair guides in this category.