Okay, here's an interesting problem. My laptop (Dell Latitude D830) developed a display issue over the weekend. Ready for this? It only works with a driver. By that I mean that the display only turns on when Windows 7 has loaded to the login screen. Before that it's black. No POST screen no Windows loading screen (no, I don't have it turned off), nothing. This is only true with the display itself. I found out on accident that it will in fact output POST and loading screen to an external display running at 780x400@70. The brightness adjustment has also gone nuts. It now only has two levels of panel brightness instead of the 6 or so it used to have. They appear to be all the way on and all the way off, but I cannot confirm this. Forthermore: The display doesn't turn off when the lid is closed, and when I open it back up, THEN the display shuts off and cannot be turned back on. In this state the backlight stays on but the panel is blank. A hard reboot is required. So far I've reinstalled the driver. Not simply reinstalled, but uninstalled and then clean installed. This is what confirmed for me that the display does not work without a driver. Once the old one was removed the screen went black (no backlight). First I tried a simple reboot to see if Windows could get by without the nVIDIA driver which it didn't, so I tried plugging it in to the TV and viola, there sat the login screen. From there I installed the new driver and when it requested a reboot, I forgot to unplug the monitor. That's when I noticed the POST screen on the TV so I unplugged the cable to see if I could see it on the laptop display which I could not. This model sports the nVIDIA Quadro NVS 140M (specs here) This laptop is no stranger to awkward failures. About a year in to its life the Core 2 ate it's own L3 cache. That's right up and burnt it out leaving everything slow as molasses. That being said, my suspicion is to a memory failure. Since there is a block of dedicated vram, my suspicion is that part (but not all) of it is gone. This is why it was able to drive the 740x400 display during post, but not the 1280x800 display it was born with. It would also explain why the system works just fine once the driver is loaded and can shuffle things around to avoid the bad blocks. My next step is to run memtest and check for bad blocks (I was clean some 9 months ago). Any other suggestions / bright ideas? I realize this is a bit of a longshot but this laptop is pretty much all I have for the next 3 months while I'm in Germany. It's old enough now to need replacing sooner or later, but like hell am I going to pay the prices over here. I'd much rather wait and get back home and pay half the money. Thanks!
Ok, so on a external display, you see the Dell logo at boot and everything bur not on the laptop screen, correct? If so, than you must know that when you are outside of Windows (BIOS/POST) the graphic card only outputs on the primary display. So, right now, your GPU thinks that your external display is the primary one, and not your laptop. Here are things you can try: -> Go in Windows, with both display connected as extended dual screen setup. And in the screen resolution panel, have Windows identify them, and try to swap them. This will tell the GPU to swap the monitors. Once done, restart your computer, and see if it helps. -> While the system is turned off, NOT plugged in, and NO battery, open the bottom of the laptop. Here is the service manual of your laptop: http://support.dell.com/support/edocs/systems/latd830/en/SM_EN/index.htm Now what you want, is to unplug the LCD plug of your laptop, turn it on without a screen, and let it go under Windows. Once in. Plug the laptop LCD monitor plug. To access this plug check the first step here: http://support.dell.com/support/edocs/systems/latd830/en/SM_EN/display.htm#wp1105347 In your case, the plug seams to be under your keyboard. So check the instruction (it's mentioned and linked in the article) how to remove it. Don't worry, it's a Latitude, they are easy to service. Either solution, should solve your problem.
No INTENTIONAL changes to Windows/software, the problem began after a hard reboot shortly after playing bioshock while out with no wifi. Occasionally one of the network services gets cranky when it starts back from suspend and the hard reboot is required. I'll take a look at the display swapping today and see what I can come up with. It isn't a hard teardown, it's one of the reasons I love these Latitudes. I usually do a complete teardown once a year and pull a mat of dust out from between the radiator and fan so I'm quite familiar with the innards.
