CPU Fan header question

[Pabz0r545]

Is it safe to plug a 3 pin CPU fan header into a 4 pin CPU fan header on my mobo? I am re building my old computer and I purchased an aftermarket heatsink but it only has a 3 pin header on it, and the mobo only has a 4 pin header.

Thanks.

[Arinoth]

Yep, that fourth pin is actually the PWM (Pulse-Width Modulation) wire, essentially it allows the computer to control how fast the fan speed is without altering the amount of voltage delivered to it. 3 pin fans can only have their fan speeds changed by changing the voltage delivered to it.

[Pabz0r545]

Thanks for the swift reply! :)

Is it safe to assume that the CPU fan will run at full speed automatically in this case?

[Arinoth]

Yep, that's a correct assumption.

[Pabz0r545]

Ok to make a long story short, when I got all my parts for my new computer I dis assembled my old pc to give it a good dust with can of air and a cleaning. I then set it back up and tried to post and got the message:

"Error: The System Fan Has Failed!Service PC to prevent damage to the system.
Press <F2> to Continue"

So I ordered a new CPU heatsink/fan thinking the fan had crapped out on the old heatsink. It arrived today and I installed it. Set up the mobo, ram, GPU, and PSU to see if the system would post and I am getting the same message. I read a few solutions online but they require going into the bios and I just can't seem to get in. I tried spamming del, f1, f2, f10, f11 and insert. None of them will get me into the bios. The motherboard is an HP/Asus IPIBL-LA if it helps at all. None of the parts have changed except the heatsink and the ccomputer was working perfectly fine before I decided to clean it up.

If I press f2 it proceeds to ask me to insert a boot disk or boot drive/media(sorry can't remember this exact message). And to press ctrl alt del to reboot.


I'm a total noob, and I have no clue what to do. Anyone have any suggestions?

[ilya]

Disable fan failure warnings in BIOS.

[Pabz0r545]

I'm such a noob. The warning wasn't even about the CPU fan it was about the case fan that plugs into the mobo. It was unplugged so I was getting that error code. OMG I didn't even need a new heatsink.

DOH

[uwish]

it happens