[Gave up] Dim laptop screen - Any ideas?

drcouzelis · 2014-04-26 01:31:11

The screen on my beloved Toughbook CF-29 laptop pooped out.

I few weeks ago, the screen suddenly went dim. It's running Arch Linux. Here are the symptoms:

The screen is about half the brightness it used to be.
I can still see what's being displayed, but it's difficult to read (but not "dead backlight" difficult).
The screen is dim from the moment I turn it on, from BIOS to X session.
(Super strange part) Sometimes the computer boots normally, sometimes the screen goes completely black when X is supposed to load, and sometimes X loads but I can ONLY see the mouse pointer; no windows, no wallpaper, just the pointer.

What I've tried:

I downgraded a few packages when I realized the screen was dimmer than usual, but I gave up on that idea when I realized that even the BIOS was dim.
I replaced the inverter board for the LCD screen. It had no effect.

Do you have any idea what might be wrong or what I can try next?

Thank you!

Last edited by drcouzelis (2014-05-08 20:28:13)

ondoho · 2014-04-26 08:33:44

sounds like a hardware problem, and changing the backlight (*) would have been my suggestion, too - except for this:

drcouzelis wrote:

... but I can ONLY see the mouse pointer; no windows, no wallpaper, just the pointer....

that could be graphic card/chip related? like, faulty acceleration? is it possible this could be the chip itself, not the driver?

(*) sorry, i actually meant the inverter board. which is usually the first thing to consider when your backlight dies.

Last edited by ondoho (2014-04-26 13:41:18)

mcloaked · 2014-04-26 12:51:22

Although I am not familiar with this particular laptop I did have a Samsung laptop that showed similar symptoms a year or two back, and eventually found that there was a BIOS setting for brightness that was changeable from auto to manual - in my case changing to manual fixed the brightness issue. I don't know if something similar is available on your laptop, or whether there is a key combination to control backlight brightness level but worth exploring possibly?

On the other hand if the laptop is quite a few years old then it is possible that the backlight has reached the end of its useful life, and I think that the backlight is integrated into the screen on that model. It is possible to open up the laptop and replace the screen if you have a steady hand and a service manual so that the dismantling and re-assembly sequence is available. I have replaced the screen on a couple of laptops in the past year or two, and although it is a bit fiddly may extend the life of the machine if you can find a replacement screen at a reasonable price. Also bear in mind from comment #2 that a fault in the graphics chip is also a possibility, and it is not easy to get an absolute determination about exactly what the fault is, and you may need to replace parts and hope that you are going for the part that has the fault.

Last edited by mcloaked (2014-04-26 13:08:37)

drcouzelis · 2014-05-08 20:27:23

Thank you for the replies and suggestions. I decided to purchase another cheap used Toughbook CF-29, with which I'll combine parts from the one I have to make a nice new laptop. Aside from this issue, I've been in love with this laptop.

Anyway, thank you!

emeres · 2014-05-08 23:57:42

So shaking the laptop or tapping on the back (top, centre and bottom) of the screen did not help? I would check all connection cables.

drcouzelis · 2014-05-09 00:22:33

Well, I replaced the inverter board, which means I had half of the base and all of the display opened up. No, I didn't check all of the cables. I'll check as many connections as I can the next time I have it open, but I'm doubtful that they're the cause. I could have the laptop setup on a desk, boot it three times, and get different results on the screen each time without even nudging it.

headkase · 2014-05-09 00:30:46

If from a cold boot the BIOS is dim then it is certain a hardware problem. If it was a warm boot and the BIOS dim then there is a remote possibility that the video driver banged the bits the wrong way that persisted through a reboot.

emeres · 2014-05-09 01:34:33

Just to clarify: When you say, you see the mouse pointer, do you mean that the mouse pointer is as visible as it is normally, meaning full brightness, even when the rest of the screen is dim, or is it just a little more visible compared to the rest of screen? When I use redshift or xgamma and set the temperature/gamma low, my mouse cursor is unaffected, it stands out because of hardware cursor implementation I assume. Is this a similar situation to yours?
Since all points to hardware failure of either gpu or the backlight itself, I would recommend using the display as a part of a diy projector.

mcloaked · 2014-05-09 09:59:29

It is possible to plug the laptop into an external monitor - that could rule out GPU failure?

Arch Linux

#1 2014-04-26 01:31:11

[Gave up] Dim laptop screen - Any ideas?

#2 2014-04-26 08:33:44

Re: [Gave up] Dim laptop screen - Any ideas?

#3 2014-04-26 12:51:22

Re: [Gave up] Dim laptop screen - Any ideas?

#4 2014-05-08 20:27:23

Re: [Gave up] Dim laptop screen - Any ideas?

#5 2014-05-08 23:57:42

Re: [Gave up] Dim laptop screen - Any ideas?

#6 2014-05-09 00:22:33

Re: [Gave up] Dim laptop screen - Any ideas?

#7 2014-05-09 00:30:46

Re: [Gave up] Dim laptop screen - Any ideas?

#8 2014-05-09 01:34:33

Re: [Gave up] Dim laptop screen - Any ideas?

#9 2014-05-09 09:59:29

Re: [Gave up] Dim laptop screen - Any ideas?

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