Does the Win31 software for the card allow you to specify the vertical refresh rates for various resolutions and colour depths? If so, I'm thinking I could try it on my CL-GD5428 VLB card, to get the 60Hz that my LCD monitor feels comfortable with...

There's a DOS utility on that disk called clmode.exe. When you run it, you can select different resolutions and vertical refresh rates. Eg, if you want Windows to work in 1024x768 @ 60 Hz vertical refresh rate, you can do that. The color depth is chosen when you are inside Windows 3.1. For that, you run the setres.exe Windows utility.

Also, for clmode.exe, there's a custom option where you can pick the refresh rates you want to match up with the different resolution options. However, for 1280x1024, the only option was a vertical refresh rate of 87.5 Hz , which did not work for my 19" LCD monitor.

Unfortunately CLMODE didn't work for me - somehow Windows seemed to "override" whatever I would set there, so that I could never get, for example, 1024x768/60Hz in Windows...

Perhaps you need to try this version of clmode.exe? Maybe it's an updated version? Could be worth a go!

I ran clmode.exe, and sent its output to a text file. It's included as an attachment below. It includes the version number for clmode.exe.

In my O.P., I mentioned a problem about the image being corrupted. Here's an example. I am always in control of the system - the system never crashes. It just looks a mess.

You're probably right about contact problems causing the corrupt screens, try to reseat those two socketed RAM chips.
My Cirrus Logic VLB card had exactly the same issue.

Thanks a lot for the confirmation. I remember Vogons user Old Thrashbarg mentioning this issue, about another VGA I was testing, quite some time ago now!

I just downloaded an updated version of the Cirrus Logic (5426/5428) software from DriverGuide. The SetRes and CLmode .exe files are updated versions to those mentioned in my original post. For convenience, here is this zip file. (The filename on DriverGuide is called CL542H.ZIP.)

I just removed those two RAM chips on board the card, and retested it. Unfortunately the problem with the corrupted image persists. However, if I run a game such as Quake or Doom, and just "sit there" and do nothing in the game, the graphic image on the screen does not degrade, as it does if I were to be looking at a static screen, such as the BIOS set up area.

The BIOS set up area is a good screen to test, BTW. It appears to get corrupted quite quickly. It's interesting to watch it get worse and worse, over a period of about 5 minutes.

This is a really old thread but I think it's better than to start a new one.
Is there a known tool or some string for the DEBUG or MODE commands to adjust the H-position of the video signal? CLMODE unfortunately does not provide such settings (at least I didn't find it)

marbury wrote on 2024-11-22, 09:15:

Is there a known tool or some string for the DEBUG or MODE commands to adjust the H-position of the video signal? CLMODE unfortunately does not provide such settings (at least I didn't find it)

UNICENTR, shipped with UniVBE/SDD.