I can think of a couple things to try if you haven’t done so already that may give indication on what is wrong.

You mentioned that you recently reimaged the hard drive; did you notice the problem at all while reinstalling? If not during the reinstall, how long after the reinstall did you first notice the screen blanking out? Was something installed just prior to when the screen blanks restarted?

If you haven’t done so I certainly suggest running diagnostics. Do you receive any errors running the diagnostics, does the system goes out while running diagnostics?

You mentioned that you don’t think that it is a LCD problem. Have you been using an external monitor, does the external display black out as well when this happens?

Please let me know what you find out.

TB

I'll have to try the diagnostics later, when I get home from work.

No problems during the reinstall. The first time it acted up was about 24 hours later, but I hadn't installed any software immediately before.

I have used an external monitor and that blanks out as well (no signal).

Thanks...

Sounds good. 

This shouldn't be happening with a clean image of Windows and drivers, with no new applications.  Diagnostics should give some indication if it is failing hardware. Please let me know what you find out.

TB

I ran the diagnostics from the Support page... no errors and no incidents during testing.

Hi Good Day Everybody, Sorry for posting here

I have posted this message reg. my Precision M6500 it's a core i7 720QM with nvidia quadro FX2800, bought it again as a used unit, runs great and is massive 17 inches and weighs 4 kilos, there's slight issue with the unit, It Runs ok when on Battery, but as i soon as i plugged in the Power adaptor after a few seconds of opening an apps (any app. like ie, google, ms office) the display goes black,  then using a flash light i tried to look on the lcd panel, no images aside from no backlight while the unit is still on , hdd, power indicator, fans i can still even turn on and off the keyboard backlight, just the screen blacks out without image, tried to pull the ac power to see if the screen goes back but no luck, i have to force shutdown the unit,  power on the unit again with ac plugged in it fully boots, but again opening any apps or connecting via wifi same thing happens, but if on battery everything works fine, I'm using a dell power adapter it's a 130watt 6.7amp 19.5 volts. i  tried to enable via bios ac power supply scan, and it turns up upon Boot message "WARNING: 130WATTS ADAPTER DETECTED, U MUST USE A 210W OR HIGHER ADAPTER" THE PERFORMANCE WILL ADJUST TO MATCH THE POWER OF YOUR ADAPTER"  is this causing the screen blackout using an under rated power adapter, i tried using a dell alienware 14x power rated 150W 7 amp (20w higher though) but it just last a bit longer "a few second " versus the 130 watt, then same thing happen. Is this kind of behavior common on  a precision M6500,  should it act this way, 

I was looking to buy a new AC charger if this is the one causing the problem.

Thanks and Again sorry for posting here

These are the Dell validated ac adapters you should be using:
J211H = 240W, 3-Pin, Delta (Uses 5120P C13 Straight Power Cord)
J938H = 240W, 3-Pin, Flextronics (Uses 5120P C13 Straight Power Cord)
* Go to the internet. You will need to find a seller for your region
* Do a search for, dell part J211H [press Enter]
* Do a search for, dell part J938H [press Enter]

Hi Sir Chris

But Can I use the 210w 10.8amp charger?

Thanks for the reply

Update on *my* problem... An initial run of the Dell online diagnostics showed no problems. A subsequent run of Memtest86 discovered two stuck-bit errors. I have removed the pair of DIMMS containing the bad RAM, but my hanging problem still persists.

I think I am able to quantify the behavior, though. It appears that the hang is most likely to happen either soon after power-on/wake or soon after ceasing heavy activity. My theory is that something is not taking the temperature transition (cold-to-hot, hot-to-cold) well and is causing the issue (e.g., bad solder joint, board flex).

Does this sound familiar to anyone?

Hi JRUSCHME,

your OP describes exactly my system with exactly the same symptoms. Your post above describes an assumption also that I concur with. It only started for me 3 days ago. I have run full DELL system diagnostics which return a full pass for my system, so they can not detect the issue. I am investigating currently, many people have had this issue, and many have posted desperate workarounds none of which fix the issue for them or myself.

One such thread where the black screen is covered in depth is here , note that the OP talks about a freeze, not the same, but the thread soon starts to discuss attempts to resolve the black screen issue. The only conclusion after reading over 60 pages was to replace the Mobo and/or the video card - or get a new system. I do not want to do that, my last port of call will be to bake my video card, but not before I conclude it can not be resolve through software.

I will keep this thread posted on what I find.

All the best,

Zay