Major CPU fan problem

[ConLog]

Hi all,

My computer has developed quite a serious fault.

My CPU fan has started fluctuating in speed and brightness (it is a CoolerMaster clear blue LED fan so I can actually see it fluctuating). The ASUSPROBE program is also showing varations in my CPU fan speed.This fluctuation in speed is causing my PC to frequently shut down which is very infuriating.

The problem is not the CoolerMaster fan as I've swapped it out with an identical fan but am still getting the same problems.

I have the same fans connected to the CHASSIS and POWER fan outputs and theses fans work perfectly.

To stabilise my system I have had to remove the CPU fan output to the POWER fan output although this results in the fan running full on all the time.

Does anyone have any ideas about what could be causing the +12V rail on the CPU fan output to be varying it's voltage?

Any ideas or thoughts would be very much appreciated.

TIA.

[Redfallon]

Have you added new drives or anything to the case lately? What brand/wattage is the PSU. Could be over drawing the power coming through the motherboard. One option would be a new PSU, or maybe move some of the fans onto molex connectors and get a fanbus to control the speed of the fans.

[Panama Red]

Either your psu is fading or you have a problem with the circuit feeding the cpu fan on the mobo. Have you tried a standard fan without the led's. Maybe the combination of a weak psu and the slight additional power draw from the led's is pushing it over the edge. What brand and rating is the psu?

[ConLog]

PSU is rated at 350W and is an el-cheapo I've been using for years.

This problem has reared it's ugly head a few weeks after I upgraded to the AthlonXP 3200+ processor.

I, like you, think it might be the circuitry feeding the CPU fan - which I hope it's not!

I'm going to try and swap the ATX PSU out with another and see if that is indeed the problem.

[P4ForMe]

If your bios has any automatic fan control in it. Go to it, and disable it to have your cpu fan running max power. Probably not the answer, but it is a possibility.

[Redfallon]

I think it may be the extra power draw (if any) from the new processor, coupled with the age of the el-cheap-o might mean the PSU is going south. I'd try a different one, and replace ASAP to avoid it taking out anything else if it does go.

[Panama Red]

Originally posted by Redfallon I think it may be the extra power draw (if any) from the new processor, coupled with the age of the el-cheap-o might mean the PSU is going south. I'd try a different one, and replace ASAP to avoid it taking out anything else if it does go.

Agree! The addition of the new cpu changes the equation a bit. That extra power draw is taxing the psu. You're on the right path by replacing it first.

[ConLog]

I bought a 400W power supply and hooked it up. Everything is good in the world again!

Thanks for all your input guys.