Inspiron LCD screen going black during boot up - solution

Question

I had the problem of my XPS (with Windows XP and an ATI Radeon 9800) booting up and the screen going completely black (as in turned off) when it got the Windows XP login screen. I could boot up fine in safe mode or safe mode with VGA, but no other way. Uninstalling and reinstalling the drivers would occassionally work for one or two reboots, but no more - back to the black login screen. Also, if I booted up in safe plus VGA mode, and tried to change the resolution in any way, the screen would blank out again and not come back.   I tried everything from a reinstall of Windows XP to going back to earlier drivers to changing all manner of video settings, etc. but nothing worked. I had concluded that I had a bad video card.   Well, I found the solution, and it makes no logical sense whatsoever (to me) so I would have never figured it out on my own. I found it after doing a search on this forum and reading for about an hour and seeing different things people have tried.   There is a small 'pin' that sticks out of the right hole above the power button. The top of it was barely clearing the hole, but I didn't think that was unusual. But reading what someone had posted here, I used a knife edge to pull it up further out of the hole, and sure enough it popped out another little bit (to where it is clearly an eighth of an inch or so out, and where you can easily push it down and watch it spring back up.) This is the pin that detects if the lid is closed.   That completely fixed the problem. I reinstalled the drivers, rebooted, no problem. Turned the computer off, back on, booted up fine. Upgraded to the Omega drivers, no problem. It's fixed (thanks to whoever posted that solution in an earlier thread.)   Now - why in the heck would that pin being stuck down allow me to boot up in safe mode with no problem but hang up when I tried to boot up with ATI drivers installed makes no sense. It makes no sense that with no drivers installed I could change to higher resolution and boot up with no problem, but as soon as I installed either the Dell drivers or the Omega drivers it MAY boot up fine, but most of the time give me a turned off LCD as soon as it went to the Windows XP logon screen. Makes no sense why I could install the drivers and boot up in 640x480 mode but as soon as I made any resolution change the screen turned off. Makes no sense, but freeing that pin up definitely fixed the problem. And I would have NEVER figured that out on my own.   I hope this helps some others who run into this problem and are as baffled as I was. And I hope SOMEONE in a Dell Tech Support leadership role reads this and distributes it to the tech support folks, so when someone emails or calls with this problem they have this as a possible solution (tech support was having me reinstall Windows XP, remove my optical drives (???), replace my hard drive, etc.)

sufferingcorpse · Answer

Simple: The video subsystem is **sort** of integrated in with the video display (in short, the drivers control both the LCD and the video card). If you think about it, you never have to setup the monitor.inf file with your laptop but yet you can clearly hit your UXGA or WUXGA resolutions without any extra seup....This is all part of the complete laptop driver package. When windows boots up, it begins to initialize all the drivers that are loaded in the system, thus when the login screen initializes and uses the specific windows driver (instead of VGA or SVGA mode upon bootup). Safe mode does not initialize a M.Radeon driver or an Nvidia driver as it's going into diagnostic mode. You don't go to safe mode to run Doom3 or far cry..

The little pin that you were referring to is part of the LCD package (95% of laptops (way older models being the exception) has this pin as it is a way to help reduce power consumption if you close the lid and do not need to view the display).

Make sense?

~SC

jlackey · Answer

Hmm. OK, I understand the integration of the video drivers with LCD control, but I don't understand why that pin being stuck in the down position would cause the screen to turn off the majority of the time at the login screen, or why it would cause the screen to turn off when changing from 640x480 to a higher resolution (i.e., the screens goes out immediately, not waiting for a reboot.) Or why it would work a couple of times, every time, upon an initial driver reinstall and reboot then stop working.   Don't get me wrong - the fact that the pin made the difference proves it DOES have that effect. ;) I just am having a hard time understanding the specific logic of the process of what's happening.

sufferingcorpse · Answer

The switch is known as a soft switch (meaning it needs some sort of program or instruction telling it what to do when pressed) as opposed to a hard switch (think light switch, turn off, it's off, turn on, it's on... etc).    An example of another soft switch: ATX Power supplies are a type of soft switch as well.  You press the power button, it doesn't Immediatly turn off, however it talks to the OS to see what to do (sometime you can specify a software initiated shutdown by pressing it, depending on your OS's capabilities).  But by holding an ATX switch for about 7 seconds(time depends on model), you find the switch turns off the machine.  This is because the soft switch's brain tells the power supply to cut power once the 7 seconds have passed while holding the switch in..   The older AT power supplies (See 386, 486, and early pentium era) were hard switches.  You flicked the switch, power was immediatly cut.   Now getting to your laptop:  Your laptop by itself, doesn't know what that pin being pressed down means.  To the gereral hardware, it's just another button.  To your OS (after your correct drivers are installed AND initiated) that button being pressed means the LCD panel is shut, and to cut the power to it.  It's also known as a sort of intelligent switch (although you would beg to differ, the pin is doing exactly what it was designed to do).   Also, not every switch is perfect.  Your pin being pressed in and working intermittantly, is telling me that it might not have a perfect contact to all surfaces of the switch (internally).     Safe mode will work properly if the pin is pressed or not, (and you can test this) is because the OS doesn't have the video drivers initiated (which tell the system that when the switch is pressed to turn out the lights).    Now does this make sense.  My apologies for not being clear up front.  I have a deep electrical background and I assumed you knew some other oddities involving electrical switches etc.

jlackey · Answer

Thanks - you were perfectly logical, I just didn't realize that the switch was controlled by the installed drivers but handled differently in safe mode (I assumed the same software instructions were used to read it regardless of the driver.) That now makes a lot of sense. I wish you worked for Dell Tech support - I wouldn't have wasted a lot of time doing things that didn't make sense to me at the time but were 'required' to get to the next level of support (and I don't think it would have ever occurred to them to think of the switch, even though it makes perfect sense now that you've explained it.)

snushed · Answer

I have a Inspiron 5150 and I don't see where this pin is located??? You said above the power button... I see nothing above this. Where would I find it?   I am having similar troubles... only loads Windows when I do not have my video drivers installed... and just use the VGA drivers.   Help!

jlackey · Answer

I don't know where it is on the 5150, but I assume it is similar - look for a hole or two on the strip of plastic at the very top edge of the computer, and look for a small plastic pin sticking out of one of them.

sufferingcorpse · Answer

jlackey, Just throw messages on the forum or PM (I have just figured out where that is). I don't mind going through some troubleshooting tactics with people. Heck, that's why i'm in the forum. I am constantly learning things from others.

I think these forums are great. It's a great way for people to figure out problems without having to tie up the tech-support lines and helps make the critical calls even quicker to get through (ie, hardware failure phone calls and such).

Robnorth · Answer

I have a friends Inspiron 2600 here that does the same thing, yet I see no button. Does this model have it or is there something or somewhere else i need to look or do??

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Inspiron LCD screen going black during boot up - solution

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