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cpu fan failure

Posted: Thu Nov 22, 2007 1:02 am
by s.dot
I recently installed a new fan. Only, here's the problem.

My old fan had a wire that connected to the motherboard that had four holes for connecting to 4 prongs on the motherboard.

My new fan has 3 holes for a 3 prong spot on the motherboard.

So, I connected the 3 holes to the 3 prongs, thinking it was the most logical thing to do. But then when I booted up, my bios gave me a "cpu fan failure" message, and shut down the system. I then took the 3 hole'd wire and hooked it up to the 4 prong slot (where the previous fan was plugged in). Surprisingly, it's working beautifully. However I'm a bit worried about that extra prong sticking out.

I'm a fan of things snapping together, and fitting together snuggly so I know that I did it right. It fits well, but I feel like the wire should've had 4 holes for the 4 prongs.

Am I safe to leave it like this? Or, what else should I do?

(The fan is working good though, silent and the fan blades are spinning)

Posted: Thu Nov 22, 2007 3:09 am
by Maugrim_The_Reaper
Welcome to the wonderful world of "inside the PC" ;).

The 4-pin motherboard header was brought in some time ago - the fourth pin is a fan control connector to let the fan know when to run slow or fast. Since your fan doesn't have the fourth magic connecting node, you can just ignore it - the connection marker (that arrow imprint on the plug) is the same for both. If you really want to be safe - your local PC store (or electrical PC gadget shop) should be selling adapters. Doesn't do anything you haven't done already - but many people just don't like looking at a 3-pin of anything jammed into a 4-port of anything else - it's unnatural ;).

Only thing here, is that the fan is probably running at full tilt all the time. A 4-pin fan would have better control over it's speed, so it makes even less noise when the processor temp is low (lower rpms).