Question about fan connections

[jimbosun]

hello,

i am making a new system and had some old fans lying around. my abit kt7 board has many connections for case fans but they all have three pin connectors. the old fans have only two wires coming out. can i get these to work? how do i know which two of the three to use? is one like a ground or something? can i hurt the motherboard if i just try and see which ones work?

thanks in advance.

jim

[OuTpaTienT]

jim, I have an Abit KA7 board and I have many 2-wire fans connected to it. The third wire is simply giving feedback to the monitoring hardware. For example, reporting the RPM's of the fan. The third wire is not necessary for fan operation.

You could just splice the fan wires into some of the wire coming from the power supply.

black to black
red to yellow

If your board is configured similar to mine (and I believe it is) then when installed in a tower case the CPU is in the upper left section of the board. Looking at it that way 3 of the 4 fan leads are horizontal, with the middle prong being + (red) and the 3rd prong being - (black).

The fourth fan connection is the same, just turned 90° clockwise.