# Stumped on Sony VAIO Dark/Dim/Black Screen Display



## DaveyJake (Dec 31, 2010)

After hours of scouring the Net and reading the MAIN THREAD ON BLACK SCREENS here at TSF, I don't know what else to do.

The Sony VAIO I'm working on is PCG-K25 and has the infamous black/dark/dimly lit screen.

When booting up, the splash screen with the VAIO logo appears normally lit and when moving to the Windows XP load menu, that is when the screen goes dark. Using a flash light, I can see that the LCD is working so it would appear that the backlight is the issue...

On the next boot, I went into the BIOS menu. The screen was lit up the entire time with no flickering or sudden flashes from the light to dark. The BIOS menu was up running fully lit. 

So could it possibly be the inverter? Using a multimeter, I was able disprove the inverter because it was registering strongly!

I then hooked the laptop up to an external monitor...no issues at all.

Could it be something simple like the Fn+F5 brightness? Using a flashlight while increasing the brightness, the onscreen prompt shows that the brightness is maximum.

So then I checked on whether or not it was manually setting itself to use an external display/projector. A simple Fn+F7 showed me that it was reading the LCD and ONLY the LCD.

What else am I missing? Is there a possible BIOS conflict or system configuration tweak that needs to be made? I mean, by all accounts, there is nothing wrong with the hardware. Is there a possible underlying software issue that anyone might be aware of?

Any help would be greatly appreciated! Thank you for your time!


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## oscer1 (Jan 27, 2010)

hi,

it sounds to me that you have an inverter problem. how did you read the output voltage from the inverter most multimeter's will not be able to read that high. usually over a 1000volts. it's like a ballast for the florescent lights in home or buildings.


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## DaveyJake (Dec 31, 2010)

What's considered a healthy range? It was reaching 723-730v.


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## oscer1 (Jan 27, 2010)

take a look here and see if this helps you out with testing the inverter.
LCD Inverter Test - Laptop Testing for Backlight or Inverter Failure


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