Uncreative Labs

Guest

Hi all. I've a PC/XT, with an MDA video card and an IBM 5151-002 monitor. Now, I also have an original IBM CGA card and a VGA card 8 bit ISA, but I can not make them drive my monitor (There's no image on the screen when I don't use MDA).
So, someone of you can tell me if a CGA card or VGA can drive an IBM 5151? And if yes, what need I to set to make it works? Thanks, Giacomo

Guest

CGA Can sort of but you need to change dipp settings on the motherboard before you try to install the new card as it has a different address.

A better solution is a hercules graphics card (my oppinion) with an emulator for CGA as you can use either CGA or Hi res mono.

VGA won't properly drive an MDA monitor even with modifications, so don't bother. A few have managed to get really small size images from VGA by running the signal through a home made converter but it really isn't worth it.

Good Luck

Guest

Thanks for the suggestion. I tried modifing the dip-switch settings, as this site and american IBM site shows, but using CGA I can not see image or text on the monitor. But my PC boots up properly. Please, help me . Need I to set the cga card too? Or something in the monitor?

P.S. I can see text using VGA card, but I see the same words in three or four copy on the monitor, and image is not stable. I don't know how to set the dip-switch this board, it is really old. It's a Cirrus logic Eagle II VGA.

Joined: 02 Oct 2004 Posts: 22 Location: near myself

I tried doing something like that few years ago, ibm 5151 with vga desn't work (18khz vertical 50 hz orizontal instead of 35khz and 60hz) and i strongly believe that it's the same with cga (in true cga mode). The only way to put them toghether is:
use card programming different frequency (or emulation throught dip switch)
build a little frequency divider (you will obtain half screen 12 inch/2=6inch Rolling Eyes

)
Using emulation you have the same of MDA.
If you use Linux and Xfree you can change frequency with configuration files and in that case you can obtain something better but i don't know if there is a Xfree for Linux under XT.
Good luck.

Guest

Maybe I found the reason 'cause it don't work. CGA have three pin for video signal (RGB), and MDA only one (MONO). Now, the EGA for example can be set to drive an MDA monitor, but CGA cannot be set.
I have another VGA card that can be set to work properly , but I don't have the Dip-switch map....do anyone has it? The board has two chips, Cirrus logic CL-GD520A-32PC-C and CL-GD510A-32PC-B, and the ROM name is Eagle II AVGA. The dip is a 8 switch selector, do someone has something similar and the scheme at home?

Joined: 02 Oct 2004 Posts: 377 Location: Stuttgart, Germany

There's a huge jumper archive on the internet, called 'Total Hardware 99' or TH99. Just google it and you will find it. Your card might be in there.

Guest

Hey, tanks! Maybe I found something similar, I hope it'll work properly. If it's, when I'll come in Germany we will drink a great beer togheter! And I'll pay...

Guest

If you are lucky enough to have a vga card with dipps & 9pin/15pin just start randomly changing the dipp switches until it works. Usually the pattern is NOT complex, just remember to record what happens each time you change dipps and record the VGA mode jumpering.

Good Luck

Guest

I only hope there will be a configuration right for my IBM 5151 monitor, to keep the original good appearence of my vintage PC, and run some little graphic program.
Now I look how to solve my other problem : find, in Europe an original IBM keyboard for it.
Goodbye and thank you all, in Italy now it's late! Giacomo

Guest

What slot are you trying to put the 8-bit video card in? there is one slot on the XT MB that is diffent from all the others (the one by the PS i belive) and will not work with certin cards. Try a diffent slot

Guest

Well, i meant the CGA or VGA card, try changing slots

Posted: Thu Aug 25, 2005 9:33 pm

Quote:

(the one by the PS i belive)

That's correct. It was for an ASYNC card, I believe. (I bet it's empty in 90% of XTs.)

Guest

Thanks. But wasn't it my matter. Now I know that I cannot drive an IBM5151 with a CGA, and my VGA can not generate an output in 18,5 Khz (MDA Monitors input) of frequency. I'll look for another video card.

Guest

there are 2 ways to drive a mono monitor
1) with a ibm text-only mono card
2) with a ega card set for mono text ( don't try it on any graphice mode)

this assumes the motherboard switched are set for mono

if you set the mb switches for ega or NONE-- you can drive a vga monitor
you can even use a 16 bit vga card - usually older ones will work inb a 8
bit slot, just do something to prevent the extra gold fingers from shorting

yes the slow nearest the power supply has " different timing" and is intended
for use with an ibm asynch card ( serial card)

if you have a ega card and a cga monitor setting the card switches to cga mode will permit 16 colors- nice for games.

when i used a vga card/monitor on a 8088 xt, many old games like night mission pinball would not sysch. surprisingly many other really old cga games would synch.
but displayed the old cyan and magenta UGGG colors.

clones of xt's do not have the problem with the right hand slot.

but many are 256k and will accept 640k and clock up
some things will not work, like lotus.

I have all that stuff- somewhere.
you need a big "care" package

Guest

oh oppps a mono monitor can work with a clone mono or herc graphics card.
Most import cards are herc mono-graphics compatible.
clue, it it has a simngle row of pins near the top rear, it is likely a cga card and
those are the LIGHT PEN connector.
a card with a rca connector is often a cga anc it is the composite connector
if one is marked BW it is not monochrome, it is for a B&W tv with a monochrome composite input.
the color is stripped out for visual contrast. as it would appear as shades of gray and be virtually impossible to read. or worse, i think blue comes out as underlines?

simcga cga40 will permit cga games to be seen on a herc mono-system
the ibm board will only produce STICK-type graphics.