Quoting Madrok

Hello again.
I was wondering if there was other variables that i could change to increase my contrast level on my sony fw900 monitor? I increased my DRIVE_MAX as much as it could, which made a big difference, but need more contrast.
I also increased the ABL_CONT_LIMIT, but it had no effect on the contrast, or anything else i could see.
If you could please help me out i would be very greatful. If not, please let me know either way asap so i can return the computer i'm using with the com port to do windas.
Thanks much,
RIchard

Sorry for the late reply.
IIRC, ABL_CONT_SHUTDOWN is the max amount of instaneous average contrast level allowed before an emergency shutdown is forced. I suspect this has to do with x-ray regulation.
If you set this very low, you will notice that when you switch quickly from an all black to an all white screen, your monitor will shutdown and blink the diagnostic code for ABL shutdown.
ABL_CONT_LIMIT would be the max average brightness which the ABL will dim to incase the average becomes higher, as with a mostly white screen. For example, you can notice the screen dimming when switching to an all white screen if this value is set very low. Again, I suspect this is for x-ray regulation.
I am concerned about x-rays, unfourtunately, windas's own adjustment for these ABL settings is vague and doesn't seem to work. It says:
"
IMPORTANT! Wait for luminance to stabilize.
"
Then you click continue when it does, but my colorimeter revealed no luminance fluctuation after 2 minutes. And waiting that long set unbeleviably low values in the two ABL_* registers. Such that the ABL dimming was very noticeable, and shutdown came with opening the web browser to a white screen.
Be carefull, and also, very contrasty monitors often have gamma issues.
Good luck. I will paste this message to the forum as I'm sure others, myself for certain, are interested in increasing contrast and avoiding x-ray exposure.
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About screen zooming on black->white:
I also used more conservative contrast and ABL settings to settle that out, my zooming/geometric distortion was never _really_ noticable anway, except on warmup where ~8 border pixels were off the screen. There is a resistor fix for this, which doesn't hinder x-ray protection. I'm not sure about how this whole voltage varying with apparent brightness stuff works.
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I got an email about an odd problem, thought I'd post it:
I'm not familiar with the ICs in the monitor. Windas does not calibrate pure colors, as no calibration is needed for them. If you are sure only one of the guns is 'firing' (check this somehow), and the color is not pure, then you have purity problems with the tube. The service manual details how to re calibrate it (physically, with moving the magnets and the deflection yoke).
I don't believe there is any 'processing' for the colors as a group, each color has it's own signal. Each of the guns' electrons are deflected in such a way that they only strike either the R , G or B phosphors on the screen. So the color image is really made up of 3 independant RGB images.
The only 'color processing' that I know of is the white balance settings, each color is calibrated seperately, so the only way a pure color (R G or B) could turn into to a composite color such as yellow, would be through something other than 'color processing'.
There is amplification of the 3 video signals before they are each sent to the R, G, B cathodes, but this has nothing to do with deflection, and is done independantly for each signal. This is probably what is actually adjusted by the white balance procedure.
The only 'processing' in which colors would interact would be dimming composite colors such as cyan (B and G guns together) so that their maximum luminance would be equal to a pure color such as red ( only R gun). I'm not sure if this is actually done, or if it is even a problem, I doubt it.
Try displaying a pure color(R G or B) on the entire screen, if you see more than one color, you definately have a purity error. If you pass the previous test, try displaying a gradient of each primary color from 0 - 255 ( the whole VGA true color (24-bit) signal range (sorry, I should say input singal voltages, but I forget them, your video card should be correct )). If the color of each step changes, and you know that your video card is working properly, you have a truly bizare problem. Please write me back if you know anything more about it.
(There are programs to display the abovementioned test patterns)
I think what is happening, is that your monitors deflection system is not properly deflecting the pure color images (from the R, G , B cathodes) onto the correct phosphors of the screen. It is known as 'color purity error'. Read the service manual, it will detail how to calibrate color purity,without DAS software, instead with physically adjusted magnets and positioning of the deflection yoke. That your problem is dynamic (only shows up after 5 minutes) I fear static physical adjustments may not be the problem, but they are the only adjustmets the service manual offers for purity problems.As far as I know, there are no DAS procedures/registers that deal with the deflection system besides those for geometry and convergence. Still, before you try the static physical adjustments, make sure to back up your current settigs and MPU (defaults reset) your monitor with Windas, then folow the procedures in order. The MPU reset may set registers that are otherwise inaccessible. It doesn't seem too odd to have to adjust the deflection system after replacing one of it's ICs.
I highly doubt this is a white balance problem, I strongly suspect this is a purity problem, and I doubt there are registers that deal with purity, still, try MPUing (defaults reset) the monitor with windas after you backup your settings. I'm interested in knowing how you resolve this, would appreciate a reply. Thank you.
Best regards.
donald wrote:
The following message was sent to you via secured mail form
in reply to your message at Pechorin's audio and video equipment discussion forum:

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Hi,
Last weak, my sony GDM500Ps got the deflection problem. I replaced the CXA2043Q and the proglem is fixed. However, after a few minutes, the red color is missing and the green color changed to greenish yellow. But the white color is OK. (That means, the red gun and the green gun is still function, it is the wrong signal processing). It seems the new chip causes the wrong color processing. Do I really need to use the DAS to re-adjust the settings? If so, which parameters must change? Your site does not have the explaination of each parameters so I get difficulty to try. Thanks.
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Let me know if I have the wrong idea about this, or if you can fill me in about something. Any links, pointers, or misc. info/observations apreciated.
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patrik:
Some monitors do not have a varistor for the G2 voltage on the flyback, or one at all ( the case for many newer sony monitors). My older 17" monitor did though, I wonder about the x-ray protection on it, as it didn't shut istelf down when I maxed out the G2? Scary.
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dickhu:
Yeah, another .dat will not turn out very good at all, It's almost as easy to just reset the monitor to default settings. Infact, I'd try that after backing up your original settings.
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Thanks for all your help and support! If anyone knows any general CRT information I'd love to hear about it to add it to my howto ( http://www.geocities.com/gregua/windas/ ). I think a section on general CRT concepts would do much to help people diagnose their own problems based on their monitors behavior.