Weird Fan problems

[snowy3uk2]

I have a problem with the a chip fan failure. When booting the PC the BIOS stops the load and reports a chip fan failure (additionally advises that this warning can be disabled in the BIOS). I immediately turned the machine off and restarted with the cover off so I couold check to see if the fans were spinning. I immediately noticed that the fan on the nVidia Ultra 4 MCP chip was not spinning but the main CPU fan was, although this then stopped. If I then allow the machine to continue to boot (F1 overrides the stop command) everything boots normally. I have then used the software that came with the Motherboard to check the temps of the chips. The temps all look fine with the CPU showing at 39C and the MB at 37C - well within the max tolerances. As the machine is left on and used the fans start spinning and the temps only creep up slightly.

However, the software also reports on first booting that the Power Fan is not working - it is very difficult to see but i am pretty sure that it is and after a while the software does report that the fan is working but shows a very uneven plot for the fan speed.

In summary the BIOS is telling me I have a chip fan failue but nothing overheats and the fans do seem to work when the machine has been on for a while. The MB software is telling me I have a power fan failure but i am pretty sure it is OK.

The machine is a custom build with an ASUS A8-N motherboard, the PSU is a Seasonic 500w ATX 2.0 AMD Athlon 3800 CPU.

The machine was built in December 2005 from new components.

Anyone have any ideas as to what on earth is going on?

 

[Marcus_X]

Have you checked all the fan connectors? Maybe you installed a newer BIOS version recently? Try loading the default values in your BIOS, save and reboot to see if the problem persists.

I don't know if you installed any aftermarket coolers, but at very rare occasions my Zalman CPU fan boasted a CPU fan error when booting, a simple reboot solves the problem when it happends.

Good luck,

Marcus

 

[Big B]

I'm not sure, but it's possible the A8N's fan is adjusted according to heat. The nForce 4 SLI can be passively cooled, and Asus has been pretty aggressive in going the silent computing route.

I'd check your BIOS settings and see if it will leave the fan on all the time or not.