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Video card question...

D

dafivehole

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Aug 20, 2013
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Location
Mansfield, TX
So I picked up a nice older PC (386 I think... I can't see the CPU). When I tried to connect the video cable (15 pins), it didn't match the connection on the video card (9 pins):
View attachment 31715View attachment 31716

I had another video card but it is much longer (still from the same era though). The card fit but part of it stuck out and simply sat on the chips on the motherboard. The machine has DOS 5.0 on it and the prompt came up but the screen wouldn't scroll at all once you got to the bottom.
View attachment 31717View attachment 31718

I'm not sure what kind of video card I need... obviously a shorter one that connects to a modern 15 pin video cable.

Any suggestions?

Thank you
 
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That machine looks like an XT, I can't see any 16 bit ISA slots on the motherboard (they are longer than the 8-bit slots and will capture the pins hanging out the end of your VGA card). Are there any slots on the motherboard which are longer?

The fault you described about 'not scrolling' in MSDOS doesn't sound like a video card issue. When using a 16 bit card in an 8 bit slot they usually work, i.e. you get video, or they dont. Are you sure you have your monitor adjusted correctly? Also are you sure the video is actually meant to scroll (i.e. the computer hasn't locked up)?

Can you also type at the prompt (i.e. type blindly dir) and see if it scrolls? If it does it might just be that your monitor is out of adjustment.
 
All of the slots are the same length/size on the motherboard... I can't see the CPU anywhere on the MB either... kind of weird.

I can type at the prompt no problem... once the prompt gets to the bottom of the screen, the last line types over itself, if that makes sense.

Thank you
 
dafivehole said:
All of the slots are the same length/size on the motherboard... I can't see the CPU anywhere on the MB either... kind of weird.

I can type at the prompt no problem... once the prompt gets to the bottom of the screen, the last line types over itself, if that makes sense.

Thank you
Click to expand...

That definitely sounds like a XT class system. The CPU is a DIL packaged unit - it will have a part number with '8086' on it. Usually its just below where the keyboard plugs into the motherboard.

As for the typing over that is weird. It could be a video card problem; i.e. the DIP switches on the back are set wrong. Take a look at total hardware 99, find your video card (looks like a paradise VGA card) and see if the DIP/Jumper settings match your configuration. TH99 is available here: http://www.uncreativelabs.de/th99/
 
It an XT with a mono video card in it.

That 16-bit video card probably won't work in it.

You either need a monochrome monitor or an 8-bit VGA card.

You also need to set the motherboard switches correctly for whatever video system you are using.
 
Very nice system there. Even from just the corner of the motherboard I can see, it looks like a typical Taiwanese ERSO XT clone motherboard. Are all of the motherboard chips in sockets? If they are, then nice, they usually saved money by omitting sockets.

Looking down at the motherboard with the ISA slots at the top, the CPU would be just to the right of the ISA slots. It would usually be labeled 8088, or you might have an NEC V20. There is usually a large empty socket of the same size next to it for an 8087.

At any rate, your original video card looks like a standard Monographics card, that is compatible with the original IBM monochrome display monitor and compatibles. That won't work with VGA, or RGB.

Some VGA cards like yours that are designed to fit in an IBM AT 16-bit slot *MAY* work in an XT with an 8-bit slot. Some do and some don't. Some may need a jumper set for that mode. If you see something on your VGA monitor when using this card then it apparently does work. Just be careful that extra card edge hanging down does not short with any chips on the motherboard!

In fact, the only reason anyone made pure "8-bit" VGA cards was for short or odd form factors where the cards would not physically fit.

Post a picture of the front of your VGA card so we can tell what kind it is.

XT motherboards have a jumper block where you must set the video card type. (Color, Mono, or sometimes none). It may act weird if that is not set right.
 
NEC V20 is a refined version of the Intel 8088. Basically it performs certain operations faster (i.e. in less clock cycles) at the same clock frequency. It is pretty much 100% compatible; although there are rare pieces of software which may not work 100% correctly.

Your current video card will probably work fine - as others have already posted try to find information about jumper/dip switch settings on the motherboard & VGA card. It's possible that it isn't configured correctly.
 
dafivehole said:
Here's a close up of the mono video card... no markings or manufacture name on it:
View attachment 31729
Click to expand...
I said post a picture of your VGA card. That way we might be able to identify if is supposed to be 8-bit compatible.

Did you ever check the motherboard's DIP switch settings? Usually the switches for video are #5 and 6:

* Switch 5,6
* off,off = MDA (or Hercules) Video <- this is probably how it is currently set
* off,ON = 40 column CGA
* ON,off = 80 column CGA
* ON,ON = No video or special (EGA, VGA) <- This is how you need to set them for a VGA card.
 
I have 3 or 4 of the 16-bit VGA cards... the one pictured (that I tried to use) is a paradise card. I'll post pics of it when I get home today...

Thank you for the info.
 
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Also remember, that with an XT-class machine (you do appear to have a V20 according to your photos), VGA will display (sometimes painfully) slowly, especially if it's a "low-end" card (i.e.---512K of video memory). I've used some older 16-bit Trident-based cards in an 8-bit slot with some success, and the 1MB of memory was significantly better than the much older 512K Cardinal card that I had used before.
 
I've got WD's Paradise VGA Plus cards available. It's an 8-bit VGA card for IBM PC/XT/AT based machines.

They're brand new -- send me a message if you need one !
 
I was able to pick up a nice IBM 5170 that resolves all of this for me... with that in mind, I need to get rid of this clone. It's super heavy so should I part it out? Just looking for some advice...

Thank you
 
Up to you. If everything works except the video card, it might be more convenient to sell it as a single item stating that the video card may need replacement. Parting it out has pros and cons.
 
Funny thing, I got a 9-pin to 15-pin adapter to connect the mono video card to a color monitor and I got weird blue horizontal lines that scrolled up and down the screen... the video card worked just fine with an amber monitor and the color monitor works fine with other PC's. Must be the adapter?!?

Thank you,
Roger
 
dafivehole said:
Funny thing, I got a 9-pin to 15-pin adapter to connect the mono video card to a color monitor and I got weird blue horizontal lines that scrolled up and down the screen... the video card worked just fine with an amber monitor and the color monitor works fine with other PC's. Must be the adapter?!?
Click to expand...
Even though I haven't seen it I'll bet that adapter isn't designed for what you tried to do with it. It's probably meant to run a multisync monitor with a 9 pin connector in VGA mode.
 
Stone said:
Even though I haven't seen it I'll bet that adapter isn't designed for what you tried to do with it. It's probably meant to run a multisync monitor with a 9 pin connector in VGA mode.
Click to expand...

Ahhh... that makes sense. Well, it was only $5 so I guess I'm lucky I didn't pay more for it... the description was lacking and I "assumed" that it would work the way I wanted it to :mad: My bad.

Roger
 
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