What is this video port?

[Mac collector]

I am rebuilding a HP Vectra 486/25n and it has an unusual video port. It is just like a standard VGA that modern computers use but it's missing one pin. I can use the computer now, as I have a ISA graphics card in it but I would like to use the built in graphics adapter as I only have one ISA graphics card. I have attached a pic to help in IDing the port.

 

[modem7]

That is pin 9. According to the Internet, in the early versions of VGA, pin 9 was a key (typically described as "Key [no pin]" or "Key" or "No pin"). Later, pin 9 became "+5 volts".

Look for an old VGA monitor that has pin 9 absent in its plug, or perhaps make an adapter.

 

[Lord Moz]

Or get a dremel :D (very carefully)

But an adapter would probably be best, as you wouldn't be altering your machine. Those keyed VGA ports aren't very common, so it might have some significance to someone I suppose.
If you could find a really short extension cord, you could just bend that pin down inside the shell, or get some snips and cut it off to make your own adapter.
Now that I think about it, if you look for those small gender changers, you could put a male/male and a female/female, and just take the pin out of one of the male connecters.
That would get you the shortest/neatest adapter probably.
Like these: http://cgi.ebay.com/VGA-D-sub-Gender-Changer-Adapter-F-to-F-Female-Coupler-/270607498121?pt=LH_DefaultDomain_0&hash=item3f0176bb89
http://cgi.ebay.com/VGA-D-sub-Gender-Changer-Adapter-M-M-Male-Coupler-/280576082653?pt=LH_DefaultDomain_0&hash=item4153a342dd

$1.98 and a pair of pliers and you wouldn't have to modify the machine

__
Trevor

 

[Agent Orange]

I am rebuilding a HP Vectra 486/25n and it has an unusual video port. It is just like a standard VGA that modern computers use but it's missing one pin. I can use the computer now, as I have a ISA graphics card in it but I would like to use the built in graphics adapter as I only have one ISA graphics card. I have attached a pic to help in IDing the port. View attachment 4911

A while back I had an old 486 project going and bought a VGA card off eBay. It turned out to have one pin blocked off. I believe that was a proprietary setup and I ended up exchanging it. I think the card was for a Wyse PC, but don't hold me to it. You might want to check the wiring diagram before modifying the plug.

 

[kishy]

Ah, the IBM keyed VGA port.

I found an adapter for this (it's just a male and female DE15, but the male end is missing the unused pin, and the female version will accept a monitor that has it).

 

[NathanAllan]

Have a look around, you might be able to find an IBM monitor of that era that someone is about to toss. I have one here, it needs a new video cable, go figure. But it is missing that pin, too.

 

[Mac collector]

A while back I had an old 486 project going and bought a VGA card off eBay. It turned out to have one pin blocked off. I believe that was a proprietary setup and I ended up exchanging it. I think the card was for a Wyse PC, but don't hold me to it. You might want to check the wiring diagram before modifying the plug.

I don't want to modify the plug if at all possible, As I like to keep thing stock (at least if they came to me stock if not then I am more open to modifying them)

Or get a dremel :D (very carefully)

But an adapter would probably be best, as you wouldn't be altering your machine. Those keyed VGA ports aren't very common, so it might have some significance to someone I suppose.
If you could find a really short extension cord, you could just bend that pin down inside the shell, or get some snips and cut it off to make your own adapter.
Now that I think about it, if you look for those small gender changers, you could put a male/male and a female/female, and just take the pin out of one of the male connecters.
That would get you the shortest/neatest adapter probably.
Like these: http://cgi.ebay.com/VGA-D-sub-Gender-Changer-Adapter-F-to-F-Female-Coupler-/270607498121?pt=LH_DefaultDomain_0&hash=item3f0176bb89
http://cgi.ebay.com/VGA-D-sub-Gender-Changer-Adapter-M-M-Male-Coupler-/280576082653?pt=LH_DefaultDomain_0&hash=item4153a342dd

$1.98 and a pair of pliers and you wouldn't have to modify the machine

Thanks! For 2 bucks it's well worth it not to have to modify it! :D

Have a look around, you might be able to find an IBM monitor of that era that someone is about to toss. I have one here, it needs a new video cable, go figure. But it is missing that pin, too.

I will look around for one on freecycle/craigslist as it seems like everyone is giving away CRTs like water here! (freecycle is a great place to get old/vintage machines that people would throw out)

 

[vwestlife]

I had a VGA card with that keyed port. What a pain -- just like keyed IDE cables. Before the current standard of the little tab molded on top of the connector, they would block off one or two of the pin holes within the connector itself. I still have a few of these cables in my junk box, and it seems that every time I grab one of them, the motherboard or controller card I'm trying to use it with does not have the matching missing pins, and thus the cable won't fit.

 

[Agent Orange]

I had a VGA card with that keyed port. What a pain -- just like keyed IDE cables. Before the current standard of the little tab molded on top of the connector, they would block off one or two of the pin holes within the connector itself. I still have a few of these cables in my junk box, and it seems that every time I grab one of them, the motherboard or controller card I'm trying to use it with does not have the matching missing pins, and thus the cable won't fit.

I believe in the case of the IDE 'keyed' cable, that would have been about the time the newer ATA HD convention came in to being. They went from the 40 to 80 wire cable about then. I don't think I have ever seen a 80 wire IDE cable that wasn't 'keyed', however I do have a few 40 wire cables that are 'keyed'. Just for the sake of intelligent conversation, I would like to know more about why those video cables were 'keyed'. Personally, I think it had to do with marketing. Tandy was very good and at moving pins around on their printer cables to get you coming back.

 

[NathanAllan]

Argh, I'd give you this monitor if you weren't so far away-- and you can still have it if you want. I don't have any intention on fixing the cable going to it.

Yes, freecycle and craigslist are GREAT places to get vintage stuff from.

 

[kishy]

I would like to know more about why those video cables were 'keyed'. Personally, I think it had to do with marketing.

That could very well be it...but remember that the pin in question is not used, "NC", and because IBM invented VGA, anyone who didn't include the key (or did include the pin on their monitor cord) was the one doing something "weird" or "wrong", not IBM.

Interestingly, my PS/2 Model 30 286 isn't keyed. The Model 56 is. This tends to suggest your assertion is right: the later models had the keying put in place because clone VGA monitors were popping up unkeyed.

 

[vwestlife]

Interestingly, my PS/2 Model 30 286 isn't keyed. The Model 56 is. This tends to suggest your assertion is right: the later models had the keying put in place because clone VGA monitors were popping up unkeyed.

The 30-286 has standard VGA, while the 56 has XGA2 graphics. Maybe they keyed the XGA connector so you wouldn't plug in a standard VGA monitor and burn it out while attempting to view XGA's higher resolutions and refresh rates?

 

[kishy]

XGA? Onboard graphics are VGA...

IIRC XGA was an option card. IBMMuseum, you around?

(in any event, I've used nothing but VGA with it)

Edit: yeah, VGA.
Maybe you mean the 9556?

 

[Mac collector]

Argh, I'd give you this monitor if you weren't so far away-- and you can still have it if you want. I don't have any intention on fixing the cable going to it.

Yes, freecycle and craigslist are GREAT places to get vintage stuff from.

Thanks for your offer and I would accept it if you were closer, but I think shipping would kill me!

 

[Mac collector]

That could very well be it...but remember that the pin in question is not used, "NC", and because IBM invented VGA, anyone who didn't include the key (or did include the pin on their monitor cord) was the one doing something "weird" or "wrong", not IBM.

Interestingly, my PS/2 Model 30 286 isn't keyed. The Model 56 is. This tends to suggest your assertion is right: the later models had the keying put in place because clone VGA monitors were popping up unkeyed.

Hmm I wonder if my aptiva has a keyed VGA monitor, I will have to check.

EDIT: just checked it and it does have the keyed port too, never noticed it before!

 

[tomasont]

As I recall, the old monitors only handled one resolution each. VGA was 640 x 480, SVGA was 800 x 600, and XGA was 1024 x 768. Later monitors were multiscan, and could could handle more than one resolution. So kishy, when you say you've always used VGA with it, is that 640 x 480 VGA? Or are you running a multiscan monitor at a higher resolution?

 

[kishy]

As I recall, the old monitors only handled one resolution each. VGA was 640 x 480, SVGA was 800 x 600, and XGA was 1024 x 768. Later monitors were multiscan, and could could handle more than one resolution. So kishy, when you say you've always used VGA with it, is that 640 x 480 VGA? Or are you running a multiscan monitor at a higher resolution?

The particular graphics chip only seems to support 640x480...or perhaps the 256KB of video memory is the limiting factor (I forget which amount of memory corresponds to what maximum res/colour depth). In any event, yes, 640x480 only because it refuses to do anything else. In Win95 it only works with the standard VGA driver, not SVGA.

(this, using three different monitors: IBM 6318-001 CRT, Compaq FP-5315 LCD, Viewsonic/Optiquest Q71 CRT)

That all tends to be beside the point of my sub-thread that the Model (85)56 only has VGA; it is the (95)56 that picked up XGA2. The VGA-equipped 8556 has a blocked pin like the OP describes.

 

[IBMMuseum]

...the Model (85)56 only has VGA; it is the (95)56 that picked up XGA2...

The 8556/8557 video is actually SVGA, with the same TI chip used on a microchannel video adapter. 9556/9557 units have planar XGA-2. Connectors are keyed to show incompatibility (The ActionMedia adapter is keyed to prevent an XGA-2 host), but the OP should be fine with a short VGA cable adapter having a pulled pin.

 

[MikeS]

The 8556/8557 video is actually SVGA, ...

Yeah, I've noticed that VGA and SVGA are used interchangeably almost everywhere...

 

[IBMMuseum]

The particular graphics chip only seems to support 640x480...or perhaps the 256KB of video memory is the limiting factor (I forget which amount of memory corresponds to what maximum res/colour depth). In any event, yes, 640x480 only because it refuses to do anything else. In Win95 it only works with the standard VGA driver, not SVGA...

Correct, despite the SVGA name (which would normally mean 800 x 600), it is the lack of drivers (even in OS/2) that make it 640 x 480. The SVGA /A adapter has 512Kb VRAM, but limited to the same lack of drivers. Early 8556/8557 systems had sockets to increase VRAM from 256 to 512Kb, later units even removed the sockets (because, as said, it was useless to add more VRAM).