CPU fan wasn't started and my pc won't boot.

[Stinkfinger]

It doesn't happen all the time, but every once in a while when I power up my pc, it halts on the screen where I can enter my bios and tells me the cpu fan didn't start and the pc needs re-started. When I restart everything is fine. What could be causing this?

 

[UsandThem]

What fan are you using?

 

[amdskip]

The fan on the heatsink most likely has built in rpm monitoring and the motherboard is not recieving a reading. Is it possible that it is dirty and takes a bit to spin up?

 

[Stinkfinger]

Its just the stock heatsink/fan that came with my Athlon 64 3000.

 

[CreativeTom]

Originally posted by: amdskip
The fan on the heatsink most likely has built in rpm monitoring and the motherboard is not recieving a reading. Is it possible that it is dirty and takes a bit to spin up?

What this guy said. I would crack the case open the next time you start it up and keep an eye on the fan.

 

[lenjack]

This is done to prevent the cpu from overheating, which it will do if the fan is not running.

 

[katwomansz]

I use compressed air to blow out my fans and case every month or two.
The fans especially always have a very fine coating of dust on the outer edge of the blades.
I would think there may be some dust that accumulations around the fan spindle. So try a blast of compressed air right at the center of the fan to blow out the dust bunnies there....

 

[mindless1]

You seem to have left out a bit of vital info- does the fan start spinning in this situation, or doesn't it?