Why does my laptop screen keep going dark?

Have a 2 year old toshiba laptop…screen will go dark at random times…happening more frequently. If I press the little button at top that gets pushed in when screen closes (not sure what its called, hibernate button maybe?) the screen will light up agiain sometimes. Anyone know whats causing this/how to remedy it? Thanks.

It’s hard to explain something that’s random, but did anyone change your power settings? (Start> settings> control panel> power settings).

thanx…tried that…doesn’t seem to be the problem…also when I plug in the ac cord, that also makes screen go dark most times…

There are 3 things to worry about (at least)

The settings of your 'puter. Double, triple check them. Some laptops screens get dimmer automatically when running on batteries. I know you have checked this. But check again, very carefully. A lot of time the error is with the user.

If there is a slider switch for brightness, it could be getting dirty in spots and slight nudging fixes it temporarily. (But these are nearly extinct now.) Plain on/off switches can also get a little dirty and reduced current causes problems. There are fixes but for laptops, a user is more likely to screw things up. You have to know what and where to spray. Sometimes connectors get a little loose (esp. with laptop screen connectors, a traditional weak link). If you are handy about things and don’t care if you accidently destroy it (!), you can partially disassemble it. Get to the area where the screen connects to the base and carefully remove connectors and put them back. Some are held in with locking pieces, are hidden under things, etc. Some expertise is needed.

The real dread is that there are components failing, such as an electrolytic cap. Hard to track down, hard to replace. Easier to swap out a board. $$$.

thanks…i think there may be a loose connector or something like that…when I whack the edge of the screen (I know this is probably not the best idea) it will come back on or prevent it from fading if it starts to…I guess I will have someone who knows what they r doing take a look…just wanted to see if there was an easy/free way to do it…

If you hook up an external monitor, does the external remain on and continue to show its portion of the Desktop when the TFT goes black?

haven’t tried this, as I don’t have another monitor handy, however, i believe it would remain on…the monitor goes almost completely dark, however it is barely visible and still operational under direct bright light??

Aha! Then the operating system (in near certainty) doesn’t even KNOW the monitor has dimmed, and you can pretty much eliminate drivers and interrupts and almost all other possible flavors of software conflict from the equation.

That leaves…

a) The built-in Energy Star mechanism in the monitor itself is under the impression that the computer is not being used and the routine for automatic cutoff kicks in. The “hibernate” button on top would wake the machine up from sleep and you’d get a monitor again. When your monitor goes “almost completely dark”, is it identical to the way it looks when it goes dark from sitting until the Energy Star thingie kicks in, or is it distinguishable? Mine goes dark as in “no electricity is in here, dude”, so if I saw even a faint ghost image of live Desktop activity I would eliminate this possibility as well.

b) Intermittent cable problems. It’s possible that you have a loose connector somewhere in the harness that goes from the laptop base into the lid/screen, and that as it heats up it changes shape just enough to partially lose the video signal. Then when you shut down and wait and reboot later on, it has cooled off and works normally for awhile. Maybe pushing the “hibernate” button on the lid wiggles the lid in relationship to the base just enough to make it kick up the video to normal. This possibility is harder to eliminate, but if it is worsening you may notice flickering – screen is there, screen is not there, screen is there – when you go to press the “hibernate” button, gradually getting to the point that you can make the screen reappear briefly but that it is difficult to get it to remain on.

c) The display hardware in the screen is itself going out on you. No fun, but you can buy lid/screens on eBay a lot cheaper than replacing the entire computer if the rest of it is in good shape and/or you can’t easily afford to replace the whole thing. It’s a teeth-clenching migraine-inducing pain in the butt to swap these suckers out, though. If it were me I’d bite the smaller bullet of paying a local tech to do the transplant for me, or the bigger bullet of buying a new laptop and enclose the old hard drive in a USB or FireWire adapter to move all my files over.

thanx ahunter…i think b) sounds most accurate…so, if this were the case, how would i fix it?

That’s not a whole lot of fun either, but try popping the plastic shielding off the lower half of the laptop (on a Mac PowerBook the part surrounding the hinge apparatus pops up and off, each brand and model is going to be different though) and trace where the ribbon cable goes up into the lid/TFT screen and where it leads down to the mobo. Check all connections you can easily reach, and look for frayed or pinched sections on the ribbon cable itself.

Depending on the laptop, you’ll either access most of this from below & around the keyboard or by flipping it over and dropping the bottom, or possibly a combo of the two. If you can find a disassembly guide for your own brand and make and model, it will save you many headaches and ulcers. (Little things like “there’s a hidden c clip at right angles to the retainer clamp, you can release it easily with a straighted out paper clip, slide it into the recessed area and push until you hear a ‘ping’, if you don’t release the c clip you’ll strip the male connector off the end of your ribbon cable”, or “watch out for the hidden sixth screw, it’s under the clock battery and you can’t see it until you remove the battery”).

I did a “case swap” on my PowerBook, swapping out the processor card, RAM, hard drive, modem card, keyboard, sound card, and PC-Card (CardBus PCMCIA) bus from my old one with the ruined hinges and badly scratched up case exterior and installing them in a pristine case full of substandard or non-upgraded or damaged or missing components. I’ve yet to do a screen swap, but I saw most of the hinge and display/power ribbon cable apparatus. In a laptop, everything is pretty much all in one narrow flat place (and there’s a Laptop law akin to Murphy’s law that says no part can come out until all the others have been moved out of the way first.)

In general, make a big work area and write down what you did and what came from where and take your time.

Dim video can come from a million sources - the LCD itself, the cable, the inverter, the suspend/hibernate switch, the video card… but my guess, based on that one sentence:

That little button usually referred to as the suspend switch, and if the metal strip it sits on has become bent from overuse, it will occasionally hit the switch on the board and dim the LCD, as it’s supposed to when the lid is closed. If it’s just the strip, you might be able to pry the button back up to a normal height where it won’t keep dropping with a small flathead screwdriver. If that doesn’t work, it’s likely the switch itself, and you need a pro to replace it.

As for the AC plugging in and causing dim video, that sounds more like an inverter issue - again, a replacement job for a pro.