CPU Fan Error?

Cosmo55 · 14 Jul 2010 at 16:14

I've had this problem for a long while now but I am finally sick of ignoring it.

After installing a new CPU fan - Asus Triton 81 - I get the message "CPU Fan Error!" on the American Megatrends page as the computer boots. It stops booting here and waits for me to press F1 before anything happens.

Both fans on the unit are spinning and the lights are working fine but its as if the motherboard doesn't know this. After building a new computer for someone else, I realised that my motherboard, Asus M3A, has 2 CPU Fan input pins on it, rather than just 1 4-pin one; a 3-pin one saying "PWR_FAN" and a 4-pin one saying "CPU_FAN". The new cooling unit I have only has 1 wire coming out of it, which is a 4pin connector and as such, goes into the "CPU_FAN" slot. This means therefore that the other is left alone. I'm not sure if this is the cause but it seems questionable.

Also to note is that my BIOS won't let me change the boot settings about the "Press F1 to Resume" setting - it just says "Read-Only Item!" when I try to change it.

Any comments or suggestions are appreciated

Thanks,
Cosmo

Tealc · 14 Jul 2010 at 16:19

The PWR_Fan connector is for monitoring the Power Supplies fan speed, not many PSUs have this feature but clearly motherboard makers provide this feature.

It's possible that your motherboard BIOS is not keyed to detect the speed sense coming down your coolers wire.

There may be a setting in your BIOS where you can choose Voltage or PWM for the CPU FAN monitoring, or turn off monitoring of the cpu fan if you like to live dangerously.

Cosmo55 · 14 Jul 2010 at 17:00

Tealc said:
There may be a setting in your BIOS where you can choose Voltage or PWM for the CPU FAN monitoring, or turn off monitoring of the cpu fan if you like to live dangerously.

Hmm I believe I tried to change settings with it a while ago - but I looked everywhere in the BIOS and found nothing about it. The only place I didn't look at was the CPU Configuration part - but thats because if I try to enter that area, BIOS freezes until I reboot :confused:

Muel · 14 Jul 2010 at 17:03

Done a BIOS update?

I used to get this error with my old Asus motherboard. Booting up with the fan unplugged, then shutting down and plugging it back in sorted it.

Cosmo55 · 14 Jul 2010 at 17:07

About the update... i tried that once but the software my motherboard came with can't be installed on Se7en.. only vista. I'm not sure of any other way to do that.. Also booting without a fan.. is that safe? surely shut down 5seconds later?

Orcvader · 14 Jul 2010 at 17:13

Happened to me on my crosshair III when I changed to the Fenrir. I fixed it by unplugging the fan then replugging it. Sorted out the problem just fine for me.

Cosmo55 · 14 Jul 2010 at 17:21

Right Ii tried doing that - hopefully didn't cook it much in the process.. It doesn't always come up with the error but I didn't when I booted just now.. Thanks for help guys - I hope it worked.

Muel · 14 Jul 2010 at 17:36

Do you use CnQ/speedstep? Should be fine if that's the case.

Tealc · 14 Jul 2010 at 18:31

My fan settings are in the 'PC Health Status' area of my BIOS (Award BIOS on Gigabyte board) and was also in the same named area on my previous Abit board.

Cosmo55 · 14 Jul 2010 at 22:18

Muel said:
Do you use CnQ/speedstep? Should be fine if that's the case.

I couldn't get Cool n' Quiet to ever work - it just crashes the BIOS if I try to mess with it

Tealc said:
My fan settings are in the 'PC Health Status' area of my BIOS (Award BIOS on Gigabyte board) and was also in the same named area on my previous Abit board.

Hmm, if only mine was like that.. I have a pretty old Asus motherboard so the BIOS is pretty useless. Any idea how I can update it without using the software it came with?

Temi_D · 14 Jul 2010 at 22:24

What motherboard have you got? Also did you check to see that the fan is spinning?

Cosmo55 · 14 Jul 2010 at 22:27

Fans are spinning - Lights are on, Temps are fine - Motherboard is ASUS M3A

Thanks,
Cosmo

Temi_D · 14 Jul 2010 at 23:15

Also is the fan a PWN fan (connected by 4 pins)? If so then you can just set the fan speed to 'ignored' in the bios.
My motherboard used to do this because when idle, the speed used to drop to ~500rpm. Which made it think the fan was faulty

Tealc · 15 Jul 2010 at 00:01

It's probably not so likely that any BIOS update would add significant features. Is there anything in the BIOS about shutdown and warning temperatures, that's where the fam control will be. If you just have the warning things then that'll step in and shut down if you fan does actually fail, so you could set the fan warning to disabled. You could also fit a case fan to the CPU fan header so it gets a reading, that'll work too.

Cosmo55 · 15 Jul 2010 at 16:48

Damn it still happens. I thought I had fixed it.

I can't set it to 'ignored' or the other thing to Disabled, my BIOS wont let me change anything, it just says Read-Only Item!.

My technician at work said something about "resetting the BIOS" by doing something on the motherboard? Anyone know exactly what he is talking about and how this is done?

Thanks,
Cosmo

- Just took a look in BIOS again - in the Hardware Monitor, it shows the CPU fan speed, so why on earth does it think there is a problem??

Muel · 15 Jul 2010 at 17:49

Reading your last few posts, definately sounds like you need a BIOS update to me dude.

Tealc · 15 Jul 2010 at 17:56

Maybe it's read only so that people won't go fiddling and toast their system when the fan was to stop running.

A BIOS update might help to fix the sense of the fan speed.

I've never seen this issue before and can't think what the cause could be, apart from the cooler not being compatible with your board.

Umm final thought. What speed do the fans run at and is there a warning threshold in your BIOS. The fans on that cooler may be spinning slower than your old one.