CPU fan not moving

[david_kay]

I am in the middle of my first self-build project and I now have power on the motherboard and when I press the power switch at the front of the pc, I can hear things starting up but the cpu fan does not move and I don't want to risk keeping the pdc on any longer until I know whether this is normal or not. I have fitted the cpu and fan according to instructions, it is seated firmly in place and I belive I have connected all the wires properly. does a cpu fan start moving straight away or does it wait until the chip heats up? If it makes any difference, the mother board is a Asus KV8 SE Deluxe and the chip is a AMD (Newcastle) Athlon 64bit 2800+.

[lil Jimmie]

The fan should turn right away, check to make sure the fan is pluged into the motherboard fan header properly and that nothing is obstructing the blades of the fan.

[david_kay]

Where does the fan actually drawer it's power from, is it from the power supply directly or does it pull it from the motherboard? And just out of interest, how long will the chip run without a fan before it blows? I am ok to have the pc on for a few seconds just to check whether the fan is spinning or not, right?

[diver203_98]

Actually it doesn't take but a second or two to fry a chip. AMD's don't have a thermal protection that Intel's do.
The CPU fan pulls power from the motherboard, and is connected to a small 3 pin connector near the CPU its self, and will be marked CPU Fan.

[david_kay]

So in actual fact I might have fried it already? Would I notice any symptoms, does it start smoking or make a smell or anything, or would it just sit there? It ran for about five or six seconds before i switched it off, do you think it is gone for sure?
I have connected the fan to the cpu_fan connector, also there is a four socket connector which I have connected to the motherboard itself. Should it be connected to anything else?

[Markoman01027]

is it a molex connector? If so, that needs to be connected to one of the power leads from the power supply.

I believe the Athlon 64's shut down once they get too hot..saw it at THG one time..but not too sure..somebody correct me if I am wrong.

[david_kay]

There are a male and female molex connector running off the fan but I can't see any spare connectors coming out of the power supply - will check when I get home though. The four pin connector attached to the motherboard is kind of like a molex only the pins are arranged 2x2, rather than four in a line.

[Designer]

You dont want to use the 12V (4 pin connector) on the motherboard, Basically the connector for your heatsink is a 4 pin molex through-connector, as you said you've got no spare molex connectors all you've gotta do is disconnect say the CD-ROM drive molex connector. Plug your fan into the back of the device and connect the original molex conector to the fan through connector.

It's unlikely you've fried your CPU yet. Provided your heatsink is properly fitted and you've only had it on for a few seconds as the heatsink will dissipate the heat produced even without the fan running (but not for long)

[david_kay]

Is it possible to daisy chain molex connectors? To run say a dvd drive and a cd drive on one, because the molex cables seem to have two connectors on some of them. Then I would use one of the free connectors for the fan?

[edfair]

Yeah, they daisy chain fine. That is what they are for.

[Lardass]

If you have left the PC on for only a few seconds I can't really see the chip being fried. The board however could be faulty in supplying the CPU fan or it could be the fan that has a problem because it is jammed. But you can also daisy chain them from the the power supply. Please could you pm me the PC's specifications?

[Alfie]

Newer motherboards and AMD cpus have thermal protection,as long as the heatsink was attached,the cpu is fine,the fan is either attached via the connections on the motherboard or directly to the power supply,make sure the fan isn't being stopped by fins on the heatsink,this sometimes happens when the fan is misaligned or tightened down too much.

[sigmaseven]

One thing you might try, which has happened once to me before, is try to manually move the fan with your finger. See if it smoothly spins like it should. Sometimes, at least with my P4 3.0. the little plastic holder for the fan and heatsink, if not put in right, can just barely stop the fan from moving. check it out. You might have to reinstall the heatsink and fan.

[i486]

You don't want to connect high-powered fans to the 3-pin header on the mobo as you could blow out some capacitors.

[david_kay]

OK, thanks to everyone for your help, I have now have one cpu running as cool as you like thanks to it's brand spanking new fan.