VOGONS


S3 AGP Cards (and possibly others) Too Bright

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First post, by Agent of the BSoD

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So when I originally built my K6-III+ machine, the card I chose was an S3 Virge GX2 by GVC Media Tech, and I immediately noticed that the signal was too bright. At first I thought this was a fluke of this particular card, as I couldn't find anything online about this. Recently, I purchased another GX2. It says on the card "S3 Virge / GX2 Ver 2.0" and thought that maybe this one would work correctly. Alas, it has the exact same brightness issue (and a worse signal quality too, I think this card is dying).

This is what the effect looks like. http://i.imgur.com/2SRuiG5.jpg

I still haven't found anything online about this, even for AGP cards in general. What would the cause of this be? Is there a way to fix it or am I out of luck?

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
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Reply 1 of 137, by alexanrs

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Have you tried adjusting the brightness on the monitor? AFAIK many LCDs come with atrocious default settings, and normally brightness is far too high. Mine is usually set at no more than 30%. Also check gamma settings.
I also remember some CRTs had an option to choose between 1V and 0.7V signals... you could try looking for that on the LCD menus.

Reply 2 of 137, by Agent of the BSoD

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I could adjust the monitor brightness, but I found that it doesn't look quite right even if done that way. Plus, I also have Voodoo 2s in there, so if I adjust brightness, then anything that uses the Voodoos will be way too dark and I'd have to adjust it again.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 3 of 137, by kanecvr

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I have the exact same issue with two separate cards - S3 Trio 3D agp / S3 Trio64 PCI. Both are from budget manufacturers. Picture looks like gamma has been turn up. Black is gray and colors are washed and unappealing.

I use an LCD screen so making adjustments is pointless - the cars are at fault - since I have other cards with the same chipsets witch don't suffer from this problem. You just have a low quality implementation. It might be fixable with a VBIOS flash from another card (different manufacturer) or that might kill your device.

On my cards, if I tune gamma from windows using the S3 Color utility, picture looks OK. Of course, it still looks like crap under DOS.

Reply 5 of 137, by Agent of the BSoD

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Didn't know about that color utility, but I would primarily be using this card under DOS (for its 3D API) so that's not of much benefit. I got this particular chip because it's the fastest of the Virge line, and I will also want to be capturing from it sometime in the future when I am able to do so, as it will show the best performance in games that use its API. If I have to settle for a different Virge, I can do that, I'd just prefer a GX2 if I can find one that works properly.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 6 of 137, by alexanrs

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Does it do the same thing when plugged directly (and not through the Voodoo2)?

IMHO it shouldn't be that hard to make a short DB15 cable with a few resistors/potentiometers between the R, G and B lines and ground, so these cards could still be "salvaged".

Reply 7 of 137, by Agent of the BSoD

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Yes, I've tried plugging in both my cards directly to monitor without the Voodoos, it makes absolutely no difference. (made sure the cables were plugged in securely too) I have a Mystique as well, and it's totally fine with and without Voodoo passthrough, so it's not any of my cables or Voodoos interfering.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 8 of 137, by alexanrs

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I'd guess these Virges are picky about output impedance. The VGA input impedance of the Dell monitor is probably higher and the cards use a cheap implementation that expects the 75ohm, so adding potentiometers between the signal and its return/ground would allow you to lower that impedance, which would increase the voltage drop and, then, lower the signal's brighness.

This is just a guess though.

Reply 10 of 137, by kanecvr

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Agent of the BSoD wrote:

Didn't know about that color utility, but I would primarily be using this card under DOS (for its 3D API) so that's not of much benefit. I got this particular chip because it's the fastest of the Virge line, and I will also want to be capturing from it sometime in the future when I am able to do so, as it will show the best performance in games that use its API. If I have to settle for a different Virge, I can do that, I'd just prefer a GX2 if I can find one that works properly.

Yeah, I prefer Virge chipsets as well. Good in windows and fast under dos - plus quite cheap and easy to find.

We need the help of someone who knows a lot about video cards. It's possible that the card has firmware/bios settings for brightness/contrast/gamma/colors that can be adjusted by modding VBIOS - that would probably fix the issues (if what I suggested is possible). On the other hand, it's also possible that the support circuitry leading to the VGA port is of poor design / quality resulting in poor color reproduction.

Can someone correct me / expand on this?

Reply 11 of 137, by Agent of the BSoD

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Bumping my own thread.

Anyway, got another Virge GX2, this one manufactured by Number Nine. Alas, it also has the same brightness issue the other two have that I have. Though this one also seems to be having some display problems too as the screen seems to vibrate, probably a dying card or maybe just overheating (the chip on this one does get quite hot), the first GX2 I got is totally fine in this regard so I won't fuss about it.

Still not sure what's causing it, but that's three in a row all having the same issue. I'm a little reluctant to try my hands at it again. Maybe I should just get a different Virge variant and call it good. Unfortunate, because I really wanted a properly working GX2.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 12 of 137, by swaaye

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I also got out my Aopen Savage3D card and it is indeed this way as well. It looks like the card is calibrated to a high gamma level for some reason.

Reply 13 of 137, by Agent of the BSoD

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Yeah, that's what it looks like here. I've been searching for a way to try to modify the VBIOS on any of them to fix that somehow, but I haven't come up with anything. There's just got to be a way to solve this.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 15 of 137, by Agent of the BSoD

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The thing is, I need it to also look normal in DOS. A Windows application / driver won't do unless it has the power to change it on the hardware/VBIOS level.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 16 of 137, by swaaye

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I looked in the drawer and got out all of my S3 cards. Powered them up and looked at boot screen gamma.

Correct (these all had black looking like black)
Diamond Viper II Z200 (Savage 2000 AGP)
Number Nine Reality 334 (Virge GX2 AGP)
Diamond Stealth 3D 2000 (Virge 4MB PCI)
STB Nitro 3D (Virge GX 4MB PCI)

Gamma too high (black clearly gone grey)
Aopen PA70 (Savage3D AGP)

Reply 17 of 137, by Agent of the BSoD

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That's strange indeed. The second one you listed, the Reality 334 AGP, is the exact one I just received that exhibits the problem. Very interesting.

I'm wondering about manufacturing time, for what's listed on the PCB and on the chip, in the case of the GX2. Because it's really odd that one works perfectly while an identical one does not.

Pentium MMX 233 | 64MB SDRAM | FIC PA-2013 rev2.0 | Matrox Mystique 220 | SB16 CT2230 | Music Quest MPU Clone | Windows 98SE
MT-32 (old) | SC-8820

Reply 18 of 137, by swaaye

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Yeah my #9 334 has a great picture. It's nothing like the overly bright Savage3D card that I have.
49724c416099894.jpg 11e4ae416099899.jpg 432a48416099904.jpg

I need a new camera. The lens just doesn't fully focus anymore.

The DOS image is a photo of my Dell 2405FPW set to 1:1 unscaled output. The Savage3D's messed up gamma is extremely obvious on here. You get a muddy grey image surrounded by pure black borders. 🤣

The blurry BIOS chip on the card says:
Reality334
4.00.01
100Mhz

Reply 19 of 137, by kixs

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Sometimes it's not bad that the video card outputs too bright picture... I have one old CRT monitor that it's too dim and this would actually help 🤣

I don't have any Savage3D cards, but I have many other S3 (around 20) and only one of them has this over bright output - I think it's some Trio64 or Virge chipset on PCI.

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