Last Updated on April 19, 2023 by Dave Farquhar
I dusted off my 486 the other weekend because I had some 90s nostalgia. And just like the 90s, I immediately ran into some trouble. The VGA connector didn’t fit on the 15-inch 4:3 LCD monitor I wanted to use. If your VGA connector doesn’t fit, you probably have the same problem I had.
VGA connectors used to leave out pin 9 as a key pin, to keep you from plugging the wrong kind of cable into the connector and damaging the connector. Modern VGA cables use pin 9, so if your cable doesn’t fit, check to see if the port has 14 pins or 15. A 14-pin VGA cable is almost a must-have if you travel and give presentations a lot, or are into retro computers.
Why some VGA ports only have 14 pins
VGA and its successors, SVGA and XGA, use a 15-pin connector in the same physical space as a standard DE-9 connector that the older CGA and EGA standards used. IBM didn’t want people plugging their old CGA or EGA monitors into a VGA connector and accidentally damaging the connector. You can straighten the pins if you do that, and I’ve certainly straightened a few pins on monitor connectors. But there’s a limited number of times you can bend and straighten a pin before it breaks off.
So, yes, IBM and other 80s and 90s computer vendors were trying to help us. Not every quirk about 90s computing is helpful, and this one’s outlived its usefulness, but at least this quirk started out with good intentions.
Over time, some of the unused pins in the VGA connector have taken on other uses. Today, the missing pin 9 can provide power to devices that need it. Since pin 9 is unconnected on older boards, or sometimes missing entirely, there’s no danger in using that pin for power. It was inevitable it would get repurposed eventually.
What to do if your PC is missing pin 9
Modern PCs almost always have holes for all 15 pins, whether they need them or not. It’s been 25 years since monitors with 9-pin connections were common, after all.
In my case, I had a VGA cable in my stash that had a 14-pin connection on it. I always keep my extra cables when I get a new monitor, and I always salvage the cables if I get rid of a monitor, because I never know when I’m going to need one. If you don’t have such a cable in your stash, you can find one on Ebay if you’re careful. Make sure it has the right connector on both ends. The D-sub connector is the most common type on both ends, especially on modern monitors and projectors, but some monitors use other types of connectors on their end.
While you’ll probably pay a premium since this type of cable is less common today, you should still be able to get one for a few dollars.
Modifying an existing cable or connector
If you can’t wait that long for delivery, you can break off pin 9 in a 15-pin connector by wiggling the pin back and forth. Chances are you’ll bend some of the other nearby pins in the process, so it’s a bit tedious, but doable. Or if you’re really brave, and own the machine, you can drill out the blank pin 9 on the computer’s VGA connector with a 1/32-inch drill bit. Only do this if you have a very steady hand. And you don’t have to drill very deep.
If you travel a lot, it’s well worth picking up a 14-pin VGA cable and keeping one in your travel bag. And if you’re into vintage computing, swap out the VGA cable for a 14-pin cable on the monitor you use for testing and any monitor you plan to use long-term with an older PC.
And if you’re into retro computing, modifying cables is something you may need to get used to doing.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.