VOGONS


First post, by userexec

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Looking for some thoughts from folks with more experience with CRT monitors and older graphics cards than I have. I used plenty of CRTs back in the day, but they were still well within their usual lifespan and easily swappable when I was learning to work on things, so this is something of a new problem for me.

I've got a Dell E770s CRT, an Acumos AVGA2 ISA card, and a Matrox Mystique G200. I'm attaching these to a Biostar MB-8433UUC motherboard with a newly-manufactured Athena 400W power supply.

Up until now I've just been using the Acumos AVGA2 with default Windows 3.11 video drivers in VGA and SVGA mode while I waited for the Mystique to ship in, and I never noticed anything wrong. Nice clear bright picture. Yesterday the Mystique arrived, so I removed the Acumos and popped it in and got the drivers all set up, and was immediately disappointed when the picture was just... dark. Not unusably dark in Windows, but blues that should be primary are showing up as a deep navy. Whites are a mid-gray. In games it's absolutely too dark sometimes to see what's going on. The brightness and contrast are already all the way up on the monitor.

I tried all the video modes, but didn't see a quantifiable difference to my eyes. Some may have been lighter or darker, but they were all significantly darker than the Acumos card running with default drivers.

Thinking the Mystique was going bad, I removed it and put the Acumos back in, figuring I'd roll the eBay dice again. It then occurred to me then I hadn't installed the Acumos AVGA2 drivers, so I went and did that...

Dark. Running with its actual drivers, it's just as dark as the Mystique. 640x480, 800x600, whatever color selection, everything's just dim. Switching back to default VGA or SVGA drivers it's nice and bright again.

I want to say this is a monitor issue, and that on a properly working monitor the default VGA mode would be eye-searing, but I just don't have a lot of experience with this hardware, and I don't have another CRT to compare. Flyback transformer going out perhaps? Maybe it's something else like power draw on the motherboard being too high when kicking into more demanding video output modes? Any wisdom or speculation would be appreciated!

Reply 1 of 6, by rmay635703

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Check your refresh rates

Many older monitors require a low refresh rate to be bright and clear.

My daily driver screen an AOC listed 60hz support up to 1280x1024

But in reality it looked terrible/unusable at anything above 1024x768x87i at 60hz dark and blurry

Reply 2 of 6, by userexec

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Thanks, that would make a lot of sense! I don't recall seeing anywhere to adjust the refresh rate in the Matrox software, but I'll absolutely look into that! Surely that's adjustable somewhere.

Reply 3 of 6, by zapbuzz

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I like monitors that do 1024x768 with at least 85hz refresh that means no headaches!

Reply 4 of 6, by rmay635703

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userexec wrote on 2021-07-31, 17:09:

Thanks, that would make a lot of sense! I don't recall seeing anywhere to adjust the refresh rate in the Matrox software, but I'll absolutely look into that! Surely that's adjustable somewhere.

A monitor driver that specifies

640x480x60
800x600x56
1024x768x87i

Should override the defaults, otherwise you usually have advanced settings that allow you to set the refresh and color depth independently

Looking further Matrox under 3.1 auto detects the max refresh which in my experience usually barely works,

If you have a vga extension cable and cut the pin for detecting the screen type that “should” fix your issue, very unfortunate if they locked refresh settings away.

zapbuzz wrote on 2021-07-31, 17:12:

I like monitors that do 1024x768 with at least 85hz refresh that means no headaches!

Many old monitors would specify a high refresh rate like 85hz but then when you went to use it you couldn’t make the display area fill the screen and the output would look horrible

I much rather have a bright crisp image than a high refresh with an image that looks dim, small and blurry

Reply 5 of 6, by userexec

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It seems today was my lucky day. Stumbled across a CRT monitor at the thrift store (RIC 3225, not a brand or model I recognize). Tried it and the picture is far brighter.

It does seem the Matrox software locks away the refresh rates in a way. In MGA PowerDesk, I can use the MGA Control Panel program to change the resolution, color depth, and font size (plus other acceleration features, True Color, etc.), but I've just confirmed there are no options for refresh rates. Those seem to be set in a different program called MGA Monitor Selection, which has a little popup to let you know a DDC-compliant monitor is detected and you should leave it alone. If you ignore that, it has a long list of monitor models to choose from, along with some generic Vesa modes at the end that specify a refresh rate or range, but are a minimum of 1024x768 going up through 1600x1200. No other modes mention refresh rates, and there doesn't seem to be any handy info button to see. So easy it's hard!

I guess I'll just pick some monitors until I land on a setting I like.

Reply 6 of 6, by AlexZ

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I also suspect the problem is refresh rate related. Back in the day when I had 386DX40, I had a Goldstar CRT monitor that supported:

640x480x60
800x600x56
1024x768x87i

It could display 800x600x60Hz, but the picture was darker and needed readjustment of position in software as the monitor couldn't fully recenter the image even after knob adjustment. In your case your old monitor is likely worn out and can't display image at high refresh rates correctly anymore.

I would get a late CRT monitor manufactured after year 2000. Standard 17" CRT monitors support up to 1280x1024 at 60Hz (and 1024x768 at 85Hz).

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