Sony vaio has dead back light high voltage circuit schematic diagram defect ccfl

The Cold Cathode Fluorescent Lamp derives its power, form the screen Inverter.

The screen Inverter converts power from the laptop, (Electricity), for the Backlight (CCFL in this case), and the LCD screen.

90 PERCENT OF THE TIME, the fault is the Inverter.

How to test a screen Inverter?
1) Use a sensitive multimeter, and test it,

http://www.insidemylaptop.com/test-laptop-screen-inverter-with-multimeter/

2) Or,

http://www.laptoprepair101.com/laptop/2009/05/04/how-test-lcd-screen-inverter-in-laptop/

Generally the cost of the screen Inverter is pretty economical. (Especially when compared to the price of an LCD screen)

Also ease of access is very easy for replacement. (Per se compared to a Backlight bulb)

Most consumers use this method of changing parts repair, as access to the required multimeter isn't available.
Also due to the required proficiency needed, to replace a Backlight bulb.

Screen Inverter doesn't repair the problem? Then it's on to the Backlight bulb itself.

[ The LCD screen is a composite of layers. These layers are held into the factory set position, by a thin metal Screen Frame.
This thin frame surrounds the layers like a metal picture frame. It comes apart.

It may be composed of four sides, held together with screws coming in from the side pieces, or two metal halves that come together. (And are held together with screws)

The Backlight bulb is generally placed against one side of the LCD screen layers, and is under that side of the Screen Frame.

The Backlight bulb is usually held in place by sticky tape.

Misalignment of the LCD screen layers, may result in a defective LCD screen ]

What is the laptop manufacturer name, model name, and model number? (Or Product Number. P/N )

It's going to be a long day, lol! Yeah, got it.
Sony VAIO VCP-EE31FX.

1) Screen Inverter,

http://www.laptoprepairparts.com/html/details.asp?ref=1314&category=inverter

2) The Backlight is a series of LED lights, OR a CCFL.
To replace means replacing the LCD screen assembly, when referring to the style with LED's,

Sony VAIO VPC-EE31FX/T replacement Laptop LCD Screen from $55.99 Brand-new screens (never used). (http://www.laptopscreen.com/English/model/Sony/VAIO~VPC-EE31FX*T/)

Regards,
joecoolvette