internal fan through USB pins

[blk03MitsuES]

long story short, got a hp slimline pc(amd 64 x2 am2 dual core 5200 and 4 gigs of ram:banana:) from my boss today cus the HD went dead and to his logic new pc is cheaper than new hd + windows....

when i opened up the case to take out the hd, i noticed there was a single fan in the entire thing, and it was on the heatsink. this thing most get hot cus there are no vents that i can see the fan pulling in cooler air into. this thing is pretty cramped. power supply has only 2 sata power connections, no 3 pin fan connectors on motherboard. it does have 2 sets of usb pins i could do without. so is it safe to hook up smaller 5v fans directly to the usb pins? i know if i hook up a 12v fan to a 5v connection it's going to spin slow but would it eventually burn the fan?

[x88x]

Sweet deal with the free computer. It's people like that who make life both horrible and awesome for us :P

As for the fans, it should be ok. If you look at those USB powered laptop coolers, those fans are often hooked directly into the USB power lines. The only thing you might want to check is that the USB lines don't push more current than the fans can take. I highly doubt that they do, but it never hurts to check. Also, running 12V fans at 5V will not hurt them over time. If you were doing the opposite, and running a 5V fan at 12V, then yeah, it would probably burn out over time because the voltage running through the windings in the motor would be much greater than what it's supposed to be, and over time would put them through much heat stress, eventually probably burning out the motor. Running a 12V fan at 5V, on the other hand is quite the opposite. Think of it like pushing the same amount of water through a 5" pipe as normally goes through a 12" pipe (5V fan @ 12V) as opposed to pushing the same amount of water through a 12" pipe as normally goes through a 5" pipe (12V fan @5V).

Another thing you might consider is just tapping into the SATA power lines for a 12V connection.

USB pinout (http://www.allpinouts.org/index.php/USB_-_Universal_Serial_Bus)
Molex pinout (http://www.allpinouts.org/index.php/PC_Peripheral_Power_5.25%22)
SATA power pinout (http://www.allpinouts.org/index.php/Serial_ATA_(SATA%2C_Serial_Advanced_Technology_Att achment))

[billygoat333]

just use the usb, it will be the easiest option if you don't mind running @ 5v.