View Full Version : Why does one monitor work but not another?

11-06-2001, 04:12 PM
I've tried 3 different monitors in an old 486,one will work perfectly but the other 2 will not display the graphics properly. An image can be seen but it is unreadable in windows 3.1 or the DOS shell .If i hit ALT-Fig4 i can read the dos comand promt directories perfectly. Can anyone tell me why one monitor will work but not another and is there a way to make any one of them compatable through the bios maybee or with a specific driver perhaps?

11-06-2001, 06:49 PM
Only one will operate at the resolution and refresh rate that Windows is set to. A regular VGA monitor is designed to operate at up to 640x480 at 60 Hz. A SVGA monitor can do 800x600 56Hz. Modern monitors operate at far greater resolutions and refresh rates than this. a typical setting today would be 1280x1024 at 85Hz.

11-06-2001, 09:06 PM
If the monitors are at least VGA then they should be able to be made to work, but as has been said the refresh rate could be causing the problem. The Cirrus Logic video cards came with utilities that could set resolution and refresh rate, not all cards in old 386/486's could do that. Possibly you may have one.
Try booting in DOS, change directory to windows, ie cd\windows, type setup then press enter. You will get a screen enabling you to change settings. Change video setting to VGA and re-start windows 3.1

You may also have to remark out an entry in Autoexec.bat if you do have a Cirrus Logic card, else this may over-ride the default VGA refresh rate.