display suddenly turns black

[Marin85]

Hi,

I have been struggling with the following problem for a few days now: while working, the display suddenly turns black, the laptop continues to function though, i.e. audio, hdd, internet etc. continue to work. If the display has turned black and if I turn it off with a key shortcut and then press a random button to turn it back on, the display gets a little brighter for a second and then suddenly goes black. If I then turn off or suspend/hibernate the laptop, I can wait a while and after that the display works normally again (until the next time). It looks almost as if it needs to cool down.

If the display turns black and there is no ambient light, I can still see some of the contours of the image, which means the display is not really off.

At first I thought it had something to do with the relatively higher gpu temperatures (earlier I was also getting some video artifacts with HD movies, aero, Acrobat Pro), but I successfully managed to lower the temperatures since then, however the above problem appears to persist.

Moreoever, it seems that the problem occurs most often when aero is used, less often when aero is turned off (=classic windows theme), and least often when the ATI card has been disabled from the Device Manager (and reboot), i.e. VGA mode. It also happens under Linux, so I don't think it is software-related.

What could be causing this and how can it be fixed?

[davidgurvich]

Has the problem occurred with an external monitor? The description could be a problem with the GPU but might be the inverter or lcd cable. Do you have another display assembly you could test with to eliminate the GPU?

Using an external monitor can only confirm a problem with the GPU, not eliminate. Using a known working display assembly can isolate the problem.

[Marin85]

Thanks for the reply! Unfortunately, I don't have any external display here, but I will try find one, so I can observe the gpu behavior for 2-3 days in a row.

[Neil]

You are on the right track to eliminate various components. I think you are going to find that the CCFL (cold-cathode fluorescent lamp) inside the LCD panel is on it's last leg. It may even have a small fracture that is preventing it from operating when fully warmed up.

[ajkula66]

It may even have a small fracture that is preventing it from operating when fully warmed up.

+ 1 on Neil's assessment...

[Marin85]

A while after I managed to get the gpu temps under control, I have not been experiencing the problem anymore so far, and I also got the external display today, so I have been playing with it and the laptop display whole day - not a single instance of the problem occurred at all.

However, there appear to be some damage to the gpu, which reveals itself when I turn on aero and during HD movies - it produces some artifacting here and there, but nothing major. Most likely, I had caught the high gpu temperatures too late. I don't exclude the possibility of a bad driver (no official Win 7 driver from Lenovo for this gpu) since I don't seem to get any artifacting under Linux.

I will continue playing around with both displays, the laptop screen has been pretty stable so far.