[Satellite A100-237] Dithered screen

Hello,
I have problem with my screen on Satellite A100-237. Some colors (lots of them; but some others are displayed correctly, without this problem) looks like dithered, example:

http://img59.imageshack.us/my.php?image=lcdmg2.jpg
(click again for original size)

The fill on the left should be one solid color, but you can notice some sort of texture (groups of darker pixels) - like if the screen was trying to simulate the color, which it wasn't able to display (technique called dithering, used in GIFs for example). When I change bit depth to 16 bit (I use 32 bit), it is better for some colors (like the one on photo), but it still presists. It is very distracting, especially in videos or games - the picture on the screen move, but this "texture" remains in one place, so it is very easily spotted.


Can I do something with this? Is it a HW or SW fault, or is it considered as "normal"? Does anybody have the same problem? PLEASE ADVISE. THX.

 

Try Dead Pixel Buddy and test the screen with all of the colors and see if this "texture" persists. If it does, we're probably looking at a screen/GPU problem rather than a software one.
Also try and see if the "texture" is in place after you shut the notebook down and the screen is inactive with a flashlight.

 

All colors from the program (thx) are displayed correctly, but when I use gray, the problem appears (with lightgray the pixels are lighter instead of darker).

I can't observe anything like that on inactive screen.

 

Hmm... Mine does that too... in certain greys, for example when you are in the Internet Options box on IE... there is a slight texture to the white thats in the background.

 

Whistler> Yes, I see it in Internet Options dialog too. Another place is the gray color around canvas in MS Paint...

What notebook do you have? Same Toshiba?

 

From your last posts, I'd say its more software - I'd try reinstalling the GPU drivers for your notebook and see if that does anything.

 

So. I tried replacing original drivers with Omega Drivers - same problem. So I uninstalled them and installed original ATi driver from Toshiba (driver from ati.com doesn't work) - still the same.

Even on Windows VGA driver (reboot after uninstalling drivers before installing others) the problem was the same.

It looks like BIOS (I have the latest I was able to find - 1.70) or HW problem.... :-(

 

This is very odd - now that we've ruled out its a software problem (based on your last post) try running your notebook throught an external screen and see if you get the same/similar problems.

 

I tried with CRT display and nothing like that appeared (no matter of resolution, refresh rate or mode [cloning/extended desktop]) on the external screen...

 

I made a simple program showing different shades of gray (RGB color [x,x,x]) in maximized window and noticed something:

1.) color RGB[40,40,40] is perfectly displayed (solid; all pixels are of the same color)
2.) RGB[41,41,41] is same as RGB [40,40,40], but groups of lighter pixels appear
3.) RGB[42,42,42] - is still same, but more lighter pixels appear
4.) RGB[43,43,43] - even more lighter pixels appear (so now it looks like groups of darker pixels in lighter solid color)
5.) RGB [44,44,44] - again displayed perfectly solid color

And it cycles this way every four shades, except that, that in shades higher than 64 (lighter shades), some artefacts appear in the fourth colors too.

So it looks like if the screen was able to display only around 64 shades (or even less) of gray and it is simulating the rest through dithering... Isn't it too few?

This applies to 32 bit. When I lower the bit depth to 16 bit, the texture (groups of pixels) are still visible, but no colors are changing in four shades, and on the fourth, overall color change (the lighter and darker pixels both).

Does anybody have any ideas?


PS: If it is too complicated or incomprehensible, I can make photos. Also if anybody wants that program, write here and I'll upload it somewhere.

 

So. I found on the Internet, that only 18 bit screens are sometimes used - and this absolutely conforms to my results (18/3=6 bits per color; 2^6 = 64 shades of red, green and blue [thus gray too, as it uses all three colors at once]).


It is very disappointing, as Toshiba L20 or even my friends old Acer doesn't suffer from this issue. If you plan to buy A100, be aware, especially if you want/need good quality graphics on internal display. :-(


EDIT: I found, that almost every ntb display uses 18bit display, so the problem is not in the low screen bit depth, but bad dithering used. Does anybody know if the screen dithering is made by software (and thus is fixable by either ATi or Toshiba) or by hardware?

 

My A100 with the problem is the Intel 950, so I'm guessing its not ATI thats causing the problem...

 

So, it isn't graphics card issue.

On Toshiba forum somebody advised it is a BIOS problem from 1.50 and installing BIOS 1.30 should help. Unfortunately, the only BIOS I was able to find is 1.80 :-( The good thing is, that it is SW fixable...

 

I found the 1.30 BIOS on one forum, downgraded and the issue disappeared! The picture is now very clean and a lot nicer than before.


Download here:
http://www.sendspace.com/file/odf8d3


WARNING: You are downgrading at your own risk. I have tried it only on my A100-237.


PS: It is very sad, that one have to use 5-version old BIOS (most recent is 1.80) to have normal picture... Toshiba have to do something about this :-( (I am going to contact local Toshiba ASP when I'll return from vacancy, or you can do too ;-) )

 

Hi 3xP053r , I just bought an A100-237 myself, and I encountered the same problem with the screen. So I am thinking of downgrading the bios to 1.30, in order to get rid of the dithering prob. But before I do that can u please tell which model do you exactly have? Is it PSAA9 or PSAA8? I want to make sure we have the same version so I can safely use the bios you provided (thanx a lot btw!!!).
I will contact toshiba as well, to let them know about this problem and ask them for a new bios where everything is hopefully fixed.

 

I have some sort of small stains all over my notebook's lcd screen. There are visible on a uniform color and even more visible when I duck a little. They seem to be under the shiny layer. Is this what are you talking about?

 

DreamchaserGR> I have PSAA9, but I think it should be universal - on the page where I found it, there was no mention about versions... Before downgrading, prepare a CD or floppy disk with newest BIOS (found on Toshiba site), so you can upgrade back in case of problems. And if I remember correctly, the update program checks whether the BIOS being flashed is compatible...

But, my ntb doesn't work from batteries now - I havent tried using the new BIOS again to check whether it is really caused by the old BIOS, but it looks like it is. When I start the ntb from bateries everything goes well until Windows logon screen - instead, blank screen appears and only HW reset helps. So it looks like Windows drivers issue with old BIOS as the ntb boots normally and even mouse pointer is displayed (and is operable by touchpad) for a couple of seconds before the screen goes blank. Same thing happens (blank screen) when I pull of power cord while Windows is running. So now the choice is - bad display or no battery operation...

As soon as I return from holiday (thats the reason why I am using different account, sorry for that) Ill contact the Toshiba and ask them to issue a new BIOS.

eStatic> Yes, that is the thing that I am talking about. You can check photo in my first post (click again on opened image to view it in full size):
http://img59.imageshack.us/my.php?image=lcdmg2.jpg

As I said, it is caused by wrong dithering technique used - the screen is only 18 bit (that means it can display only 64 shades of each RGB color) and it simulates the 32 bit mode (256 shades of each RGB color) via dithering. Most screens quickly cycle the color of the pixels, so you cant notice it, but for some reason, BIOSes newer than 1.30 do not cycle it, but they display it statically - like GIF images does.

It looks like that every A100 with newer BIOS does this, so this should be the problem you have.

The solution is downgrading to 1.30 (but notice above that I have problem running ntb from battery with that version), or forcing Toshiba to issue new BIOS that should fix this issue...

 

Hi, I come from an italian forum in which we are talking about the dithering problem. We found we can solve that with 1.30 BIOS, and we found also the batteries problem.
To solve that you have to disable the "ati power play" from the control panel.

I have not bought yet the notebook and i hope them will fix those problems!

 

L'Esattore: THANKS A LOT! I knew it was driver issue (as the ntb worked without problems in safe mode), but I didnt knew which. Thanks again!

Have anyone from the forum contacted Toshiba - in the case - what they said? I am going to ask them so in next few days (I was on vacation)...

 

I have just found a BIOS update from yesterday (version 2.00) on official Toshiba-europe site and it looks like, the "dithering" problem is finally solved!

 

So, the BIOS which is updated by Windows utility (named 2.00WIN) is different from BIOS updated by boot CD or floppy disk (named 2.00TRAD), probably by mistake, normally it should be the same.


But the WIN BIOS still _has_ the dithering bug, in TRAD it is fixed. So if you want to get finally rid of the dithering problem, update to BIOS 2.00 by boot floppy disk or CD (download 2.00TRAD, unzip, go to CD-R/CD-RW folder, burn the .iso file to CD, restart notebook, press F12 on boot, select CD/DVD and the rest will go on automatically).

 

Thats cool that toshiba realeased a update as soon as possible and that the issue is fixed. you must be happy

 

Thanks about this info 3xp053r!!! unfortunately I don't have a blank cd-r at the moment to try this. Once I get hold of one I'll do the bios update.
I've contacted toshiba some time ago, although I didn't get an answer.
But since they've released this new bios which fixes the problem I can't hold a grudge to them

 

Thanks 3xP053r!

 

It looks like the Windows version of the update got fixed, so if you haven't upgraded yet, now you can do it from Windows, too.


madonion> As soon as possible? I haven't tried myself, but people who advised using BIOS 1.30 (which didn't have this problem) said, that this issue appeared from BIOS 1.40 - that's 5 versions (1.4; 1.5; 1.6; 1.7; 1.8) within 6 months and they had working code (as BIOS 1.30 was OK) - unless there was something wrong right in this code and the only temporaly solution was the one that introduced the dithering..... But 6 months is too long in my opinion (although I have bought my notebook only 3 months ago)...

 

I made the BIOS update on my Toshiba Tecra A7-112 and the colors are OK now... Thanks for your support!

 

I have Toshiba Satellite M100-179 and after updating BIOS to the newest one (2.10) nothing happened. Screen is still dithered :/

I have tried both windows and boot cd method and it didn't help.

 

3xP053r, I just bought the notebook and noticed that there is a problem with the screen, How do you know for sure that it is dithering ? should I display a certain color on the screen or what ? To avoid the problem I flashed the system with the latest bios (TRAD) and not windows, but I don't think its gone, I tried with the windows version but it says that the bios is the same and cannot complete the flashing process.

Its driving me crazy.