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ET4000 Howto center image VGA-Text/VGA-Gfx/EGA-Gfx ?

D

dr.zeissler

Experienced Member
Joined
Jan 4, 2014
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417
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Germany
I do not use any old CRT's. I mostly prefer the 15" Eizo TFT with speakers. One really annoying problem is the picture not being centered while switching between textmode 80x25 (VGA) with volkov or norton-commander and starting a game/demo/intro with EGA or VGA Lowres 320x200. My current ET4000 1MB 256color max in my Amiga 2000 is nearly fine, but the onboard ET4000w32p on my FSC PCD-4L is REALLY annoying.

If I center textmode 720x400 and start an EGA-Lowres game the picture is still centered, if I start a VGA-Lowres game the image is about 10mm to the right, leaving a 10mm black square on the left. If I do correct this with the builtin autocentering feature of the eizo you know what the textmode looks like when quitting the game.

Some GFX-Cards ware really good calibrated to have mostly all modes centered on a TFT. e.g. a Voodoo3 is fine here. Top notch are the intel integrated chip-gfx like i815e/845/865 they produce reference Output quality an d always a centered image. Matrox cards a good too, not best, but they offer a correction-tool within the Win9x-driver, but it cannot be used for dos.

So what should I do to correct this for my FSC-PCD-4L with it's onboard ET4000w32p ? Any tools known to access the picture calibration?

Thx!
Doc
 
You don't see it on your Amiga because it doesn't have text mode and unless you're running CybergraphX or Picasso or something, you're probably never changing display frequency at all.

I had an ET4000 in an AT clone a very long time ago. I had one AT clone that had a software utility for centring the image. I can't recall if they were the same machine.

Oh and probably 12 of those thread views are web crawlers.
 
Sorry, I use a secondary TFT on my ET4000 on my A2000 with PC-Bridgeboard A2286 /286/8. So it's a normal PC Setup though. The 256Color ET4000's seem to be a bit more calibrated then the Hi/TrueColor ones.
Can it be that some cards use 720x400 aka textmode to display 320x200 EGA/VGA and others switch the monitor to 640x480 or 640x400 to display 320x200?
So letting 720x400 like textmode seems to be the failure?

I don't know what these intel guys with their integrated chipset-gfx did, but they offer 100% the best picture-setting and a perfect centered image through all formats and resolutions.

Another annoying problem is the vertical lines on some older ISA/PCI cards visible on arias with the same color. Some cards have that on TFT some don't. On CRT these are not visible.
 
Now that is STRANGE! I have an identical machine with the same board with the same onboard-gfx chip that does not have this problem! here textmode and vga-lowres do exactly match!
Monitor is the same!
 
It's importaint to remember that CRTs generate video in a very different way than modern flat-panel displays. In modern displays the analog signals have to be converted back into a bitmap before being displayed, while in a CRT display the color signals are traditionally only amplified and fed directly into the picture tube. The conversion to bitmap also has to take into account things like scaling and positioning, since the flat-panel display has a fixed resolution to work with. If this conversion encounters scan-rates it's unfamiliar with, it might misbehave.

When you mention the other board, these chips from the early 90's are very flexible. It might be that the VGA low-resolution mode for one card use slightly different scan-rates than the similar mode for other card, despite them using the same chipset.
 
Both chips are onboard-chips soldered on the motherboard, but I think this is equal as having to identical isa/pci gfx-cards.
 
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