I’d left the computer running when I left the room. When I returned, it hit me how loud the noise was. Whatever that computer was doing, it was working hard.

Unfortunately it was doing nothing. That’s never a good sign. Computers that aren’t doing anything, shouldn’t be running their fans at full speed. It was time to operate.

After a little digging around in the case, I identified the four points on the motherboard where fans connect. One was taken up by the back case fan, one by the processor heat sink, the heat sink was also connected to a second point, and finally, the three front case fans that were making all the noise were connected to the final port.

Except they weren’t. Two of the three front case fans were attached to the motherboard. The third fan, was connected directly to the power supply. No wonder it was running at full speed. It was simply connected to power without any speed control. Hanging down from the top of the box was an empty socket on a piece of wire. It looked exactly like the socket the fans were attached to. Sure enough that wire was also connected to the other two front fans. Clearly somebody had wired something up wrong.

I connected the third fan to the same wire as the other two and rebooted the machine. The third fan didn’t light up and start spinning.

Is this why that fan was connected to power? Perhaps there isn’t enough power coming out of the fan ports to run three fans. Google time. This seems to be a problem common to those who build PCs. There is a power limit to those ports, but I was nowhere near mine.

So there wasn’t a problem with the fan. I could get two to run at the front, and it didn’t matter which two. Then it hit me. It’s the triple adapter they’ve used to plug them in. When trying to run different combinations of two fans, I hadn’t actually connected either of the two working fans to the socket that the third one didn’t work in. I tried it, and they didn’t work. IT’S THE WIRE!

The only thing that worries me is how the person building the thing didn’t try that out themselves.