Sometimes when you’re fitting a motherboard into a case, especially an aftermarket board into a name-brand case, the connectors for the panel LEDs and switches don’t match up with the board. You can usually rewire it fairly easily, but extending them means splicing the wires. But there’s an easier solution, and it’s cheap. Here’s how to rewire or extend case front panel connectors with plug-in connectors.
I ran into this on my IBM PC/AT. Its HDD connector wasn’t long enough to reach an ISA IDE card because it was designed for a full-length card. And the LED for the power light didn’t reach either. The problem is less rare with recent hardware, but not non-existent.
You need DuPont jumper wires
The key is knowing what to ask for. Case extension cables exist, but they’re not easy to find and tend to have a premium price attached to them. But you can do the job with cheap DuPont jumper wires, intended for prototyping use. They come in lengths ranging from 10 to 40 centimeters, which is 4-16 inches. That’s a wide enough range to cover almost any use.
You can get a pack of 40 for a couple of dollars.
The connectors for the front panel are called DuPont connectors, which may or may not be news to you. The jumper wires have a male DuPont connector on one end and a female connector on the other. They happen to be the same type of connector used for prototyping. So we might as well use them too.
Using DuPont jumper wires to extend case panel connectors
To use them, just peel off the number of wires you need. Then plug them right in to the existing connector to lengthen it. It takes some luck to match the color coding exactly since they come in random colors and the ones you need may not be in the same order. Since I usually use them in pairs, I try to match one color to make things easier.
Plugging them in takes less time than picking the colors to use and is completely reversible, which is a boon for vintage cases you may not want to extensively modify. The connector makes a strong enough connection to hold on its own, but you have a couple of options for securing it. You can use a bit of electrical tape, or if you have enough slack, double back a little bit of the wire onto itself and then secure it with a zip tie. The zip tie option won’t leave any residue if you ever have to remove it.
I find that in desktop cases, the 10-cm jumpers are long enough for most uses. I don’t want too much extra length because then I just have more slack wire to bundle up and manage. If I did this a lot, I’d buy several lengths. Since I don’t need them very often, I’d be inclined to just use two jumper wires if I need to extend case panel connectors more than 10 cm.
Using DuPont jumper wires to rearrange case panel connectors
Sometimes you get one big jumper block that doesn’t line up with the connectors on your particular motherboard. Late 90s Compaq cases tend to be like that, but I also have an Everex AT-style server case like this. I can usually rewire Compaqs, but the Everex is just a ribbon cable with a 12-pin connector crimped onto the end. There’s no easy or reversible way to rewire that. The odds of me ever finding an Everex board to put in there are slim, but they aren’t zero.
Here’s what you can do instead. Find the wires that correspond to each connector, then plug jumper wires into the block to break out individual connections like the power LED, hard drive LED, and reset switch how you need them. Then connect the jumper wires to the appropriate motherboard leads.
I don’t like permanent modifications to vintage hardware when I can avoid it. I don’t know what options I’ll have next year, or five years from now. So I like to keep them open.