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10-16-2020

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Recurring black screen + sleep problem

2020-10-16, 16:04 PM

Hello all, newcomer to the forum here. Question concerns my Thinkpad T420, which I've owned for ~5 years now. Had very few problems with it, but one recurring issue has just cost me a lot of data, and I finally feel that it's worth the trouble of asking about it.

 

Every now and then, my Thinkpad's screen turns completely black and will not restore to normal visibility under any prompt whatsoever. This occurs rarely, but appears to be increasing in rate.

 

On some of these occasions, I have been able to work around the problem by inducing a sleep state in my machine, which always solves the problem. Since it's near impossible to use the keyboard and mouse without visual input, this solution usually involves holding the power button for a short duration or unplugging the cord to change the power settings.

 

However, for the last two instances this solution has been unavailable. No matter what I try to do, the machine will not go to sleep. I have carefully inspected and adjusted all the sleep and power settings available in control panel, and I know exactly what does and does not turn my computer to sleep. When the black screen issue occurs, the sleep options ALSO stop working, and that is very troubling.

 

So I find myself starting at a black screen, with a machine that will not go to sleep no matter if I pull out the plug, close the lid, hold the button for 1+ seconds or attempt to navigate options via keyboard without any visual feedback. The one time I just closed the lid and pulled the power plug, the laptop remained on until it ran out of battery and then shut down completely, losing everything on the machine in the process.

 

Just today it happened again, and this time after reattempting all options in futility I was forced to manually shut down, restart and lose all data. What's strange is that I had put the machine to sleep the night beforehand - I watched it - and yet when I went to starting using it the next day, it was already on, with the black screen. It was as if it had turned itself on in the night and then gone into black-screen mode.

 

So there's the details of the case in long. Short form:

 

  • Laptop screen goes black and will not go into sleep from the normal prompts
  • Happens out of the blue unexpectedly and at an increasing rate
  • Seemingly no choice but to accept the loss of all data on occurrence

 

If anyone can shed any light as to what is happening to my machine, it would be greatly appreciated. My expectations for fixing this sort of issue are realistically low, but if anyone does have a surefire fix, preventative or workaround then I would be overjoyed.

 

Thanks, LPSP

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12-11-2015

US

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Re:Recurring black screen + sleep problem

2020-10-16, 22:52 PM

What version of Windows are you running?

 

My guess is that your system is actually trying to enter a sleep state, but is bluescreening (crashing) instead and thus cannot resume from the sleep state.    If it is bluescreening there usually will be a memory dump of the last crash created in C:\Windows\MEMORY.DMP and multiple time/date stamped minidumps created in C:\Windows\Minidump\*.dmp

 

If those are being created around the time you notice the black screen (or when it went into sleep mode) then those files could point to the device driver causing the problem.

 

There is a free utility called WhoCrashed v6.65 that will read the memory dumps and try to identify the file (usually a .sys file) that is associated with the device driver that crashed    If it does not identify the culprit, then you can zip up the files and attach them to a reply, and either myself, or someone else can open the .dmp file and try to identify the cause. 

 

This is usually caused by a corrupt or outdated driver failing to enter a low power state, so make sure you have the latest drivers installed on your system. 

 

 

Cheers,

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10-16-2020

GB

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Re:Recurring black screen + sleep problem

2020-10-17, 2:52 AM

Thanks for the input, JDGillis. I am running Windows 7.

 

I had a look at the MEMORY.DMP file - it was last updated 17/04/2018, 2.5 years ago. I vaguely remember a problem around that time, which plausibly could be this issue, but I've had other issues since then - no crashes, just this black screen business. The minidump collection aligns with this date, with the most recent minidump on the same date and the others occurring earlier in 2018 and in 2017, when I had only had the laptop for a brief period.

 

Ultimately, if the computer did crash, surely it would restart - blue screen of death and all that - rather than lingering in the black screen ad infitum until I hold down the power or pull the plug and let the battery drain? Moreover, whenever I have seen a blue screen or similar, if I press buttons on the keyboard, nothing happens. Whereas with these black screens, if I press say the space bar or enter, I recieve audio chimes just like if you hammer these keys during normal useage without a prompt. From experimenting with options like Ctrl+Alt+Del and Alt+F4 and then listening for the audio chimes when I press the arrow keys, space, enter etc., I have reason to believe that the respective functions of these keyboard shortcuts are operating as usual and that my desktop activity is awake.

 

This suggests that the computer is essentially running fine but the screen isn't activating for whatever reason. This is further reinforced by how, in the earlier instances when the machine would let me put it to sleep by quickly pressing the power button, or unplugging the computer and closing the lid as per the control panel settings I always use, the computer dutifully sleeps and then reawakens just fine with the screen working as usual.

 

For thoroughness's sake and general interest, I'll happily run WhoCrashed and have it assess the earlier minidump files in my computer in order to scrape for issues, although it seems unlikely that they'll pertain to what's happening with my machine.

 

Thanks, LPSP

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