Picasso's graphic cards questions

[CrashMidnick]

Hi all,

I have 2 little questions about picasso GFX cards :

1) My Picasso IV scan doubler/FF generates vertical lines on LCD screens (well known "problem"). I thought it cannot be solved as I have tried it on 3 LCD monitors and it was always the same problem. Recently I bought a 26" LCD TV, and the picture is perfect !!! The settings are exactly the same...

Do you know why ??


2) Overclocking a Picasso II : is it possible whithout burning everything ?? The reason why I would like to know is that in 800X600x16, the clock speed is too slow for LCD screens (I cannot get it working on my monitors, It works on my TV but there are horizontal lines moving down and up like when you want to take a picture of a CRT screen)... and I do not want to use CRT screens anymore...

Thanks.

 

[davideo]

I've not experienced the problems you describe with my PIV but I have lost the colour (or at least got a very unstable colour) on odd occasions and it has always proved to be a problem that the card has moved.

A quick tighten up or loosen of the bracket screw normally fixes it.

Is your card moving around as you unplug and plug in different monitors.

Dave G

 

[CrashMidnick]

Both, the PIV PCB and rear bracket are quite soft. So when I plug and unplug many times the VGA connector to make tests, I always do that when the computer is powered OFF. So I confirm that the board is moving. Enough to make a shortcut ? Don't think so but I prefer to avoid any risk.

Concerning the "lost colour", I have quite the same problem on another PIV and it affects only the SD/FF : All colours are ok, just the white is purple. It happens some time. In my case I have to plug and unplug the SD/FF ribbon cable which is boring as I need to open the A2k case each time. This PIV is very strange as it can runs flawless during 1h or 24h but everytime I switch the computer OFF, It cannot boot If I switch on the computer just after . I have to wait 10 minutes to be able to boot again. The funny thing is that I can make as many soft reset as I want, It will always boot... Cold Reset always fails !!

For your problem I am pretty sure that it is (If you never have freezes) :

or your VGA cable
or your VGA connector on PIV

For my problem, the board is working well in my A3k, cold reboot is OK and never had any "purple white" meaning that it is an A2k motherboard problem related... That's why I decided to buy another MB rev6.2 but did not have the time to test it yet.

 

[BLTCON0]

1) My Picasso IV scan doubler/FF generates vertical lines on LCD screens (well known "problem"). I thought it cannot be solved as I have tried it on 3 LCD monitors and it was always the same problem. Recently I bought a 26" LCD TV, and the picture is perfect !!! The settings are exactly the same...

Do you know why ??

I don't, but I will dare a guess.
From my own PIV experience, these 'vertical lines' are very very very slight and subtle variations of brightness. I actually like them, it makes my gray Workbench screen have a paper-like quality and after a couple of hours I stopped noticing them anyway.
Now, 26" LCD TVs are very cheapish in general, so I wouldn't be surprised if they have 3 x 6 = 18-bit colour depth capability (instead of 3 x 8 = 24 bit) and are unable to 'catch' these very slight colour variations, as the variations would exist in the 3 x 2 least significant bits of the original 24-bit colour information. In that case, the identical most significant 6 bits would be preserved and all shades would be truncated to the exact same colour, thus giving the impression of a perfect picture, while in reality it would be a display device limitation.

Just a theory