Dark laptop screen

[Dietrick]

I have a problem with my Toshiba 2520 CDS. The screen has gone almost completely black, only by shutting down all lights in the room it is possible to see whats on the screen. It started with the light going of just for a few seconds, then a little longer. I discovered that a gentle slap on the back of the screen, or closing the lit fast, used to do the trick. But the problem has got worse and worse gradually. So now it's black all the time and there is nothing I can do to make it brighter. I have tried the BIOS, but the power settings is already on "full power" and if I change it the screen gets even darker. And by the way, the right side of the screen is slightly brighter than the left one, but it is still way to dark. And it is not the lit-closed switch either, because if I press it, the screen goes completely black. For some weeks ago, I opened up the computer and then it was ok for maybe a week. Does anyone know what the problem may be? And can it be fixed?

[ArcticFox]

I'm almost positive that your backlight has gone out. Short of replacing the screen or sending it back to the factory, there is nothing you can do about it.

[bombledmonk]

It is also possible that you have a loose internal connector. I had a similar problem with my old laptop.

[Dietrick]

The problem is fixed. It was the power inverter, located just under the lcd-screen. Cost me just 5$ on eBay. Sometimes you're lucky...

Thought I just send this in case anyone else have the same problem. It was really easy to fix, anyone can do it.

[jman01pa]

How did you determine that the problem was the power inverter?

[john_phoenix]

This is usually caused by bad solder joints on the inverted PCB. Remove it check and resolder and joints that look suspect and refit.

[Buzioid]

There were only two possible solutions if the back light had gone out, the power invertor and the lcd cathode itself.

The first choice you would make would be the cheapest, like he said, $5 on ebay for an invertor.

If that didn't work, then you would go the next route and probably have to purchase a new lcd, unless you can find a cathode to go in it.

[Dietrick]

Well, as the screen wasn't completely dark, I figured that it's not likely to be the lamp, because a lamp tends to either be broken or working - not something in between.

And when I the day before had checked on the internet for replacement CCFL's (cold cathode flourecent lamps) I saw that for every lamp there had to be an individual exact value of the voltage supply for every lamp depending on the thickness and length of it.

So then it seemed resonable that this half dark/half black screen would problably be the result of when one of theese lamps are connected to a power supply with too low voltage. So, then it must be the inverter.