286 + EGA card + 5153 = Problems

The office DOS box had to be gutted of its hercules card and 5151 monitor for a customer so I took the chance to upgrade it to color. I scavenged a Deico DEGA-S100 8-bit ISA EGA video card and set it to RGB 80x25 mode and plugged an IBM 5153 CGA monitor into it.
The result is I'm seeing text I swear is 40 column or somewhere funky in between ([url=http://home.online.no/~t-gutteb/51531s.jpg]like this though that might actually be 40 column mode) and graphics modes are a bit funky. For example if I try booting the DOS 5 install disk 1, the install screen will be partly displayed in 40 column mode, even though the switches are set for 40 column and so fourth.

Did you change the BIOS or motherboard DIP switch from MGA to EGA? My AT clone had XT style DIP switches. I think the actual IBM AT had a jumper block that needed changing.

Video mode is set within the BIOS (mono, EGA, 40 column, and 80 column). The system will say there is a configuration error if I set it to anything but EGA. I didn't check for jumpers though.

NeXT said:

The system will say there is a configuration error if I set it to anything but EGA.

Click to expand...

That's expected. For a CGA monitor connected to an EGA card:
1. Set motherboard configuration for EGA.
2. Set switches/jumpers on EGA card for CGA mode.

Check that the switches on your EGA card are set correctly. For example, instead of setting OFF/OFF/OFF/ON, you may have set ON/ON/ON/OFF (the opposite).

There was a lone jumper on the board marked "MONO" on one side and "COLOR" on the other. I switched the jumper around so now it was in "COLOR" and tried again.
No dice.


*ignore the complaining installer. It's trying to install to A: