Replaced mobo, cpu fan always full rpm. Why?

cb_boarder · Oct 20, 2008

I had an older Emachine t2800 series that had a bad mobo. I replaced the mobo with a newer better mobo (biostar p4m900-m4) and it installed just fine. However, the cpu fan runs full bore and doesn't slow.

The cpu fan and heatsink is the same that was on the stock mobo, 3 pin 60mm (it looks like.) Biostar support said that the fan may not have a pwm chip OR support fan control.

Is it likely the mobo or the fan? I know the fan varied speeds when it had the stock mobo. Doesn't that mean that it supports fan control?

DavidGP · Oct 21, 2008

Hi

Double check that the fan is plugged into the correct fan pins on the motherboard as on some mobos if its not in the specific CPU fan header port and a general case/system header fan port the fan control option does not work.

Also check in the BIOS for any settings in a Hardware Monitor section for fan control, may not have been set to enabled with this new mobo.

Edit: Also just had a quick glance at the manual for that mobo and in what order are the wires colours to the fan, the black one should goto pin #1 of the CPU header port.

cb_boarder · Oct 22, 2008

The manual says that it has settings in the bios to change the fan speed but the setting are not changeable when I open that page. They are all grayed out. All the pins match up with the wires they are suppose to.

I just requested a RMA and am returning it. It doesnt consistently boot from disc either. Probably bad. I ordered a MSI board.

If anyone has any other comments or suggestions though I would be glad to hear them. I am still curious why the board is doing that.

Log in or Sign up

Replaced mobo, cpu fan always full rpm. Why?

cb_boarder Private E-2

DavidGP MajorGeeks Forum Administrator - Grand Pooh-Bah Staff Member

cb_boarder Private E-2