It may be something in the BIOS that is powering down the fan at a certain
temperature, or a bug in the BIOS, that is turning it off inadvertently. I
had a motherboard with a BIOS glitch that caused the fan to effect what
clock speed the BIOS ran the CPU at, when the CPU fan was plugged into the
motherboard. Epox, the manufacturer, never did resolve this.
Nothing in the operating system should be controlling the CPU fan. Make
sure any power saving options are turned off in the BIOS, so the fan won't
turn off. Of course, you can always plug the CPU fan directly into a
regular power supply molax connector, which avoids any motherboard control
of the CPU fan. The CPU fan usually has a red, white, and a black wire. The
white wire is just a signal wire that relays information to the BIOS.The
black wire is the ground, and the red wire is 12 volts, which is the same
as the yellow 12 volt wire on your power supply molex lead. I don't know
why they did it this way, seems to me they should of kept all the voltages
on the same color...but they didn't. So connect the red wire to a yellow
wire, and the black wire on the CPU fan to any black wire on the power
supply. This will make the fan run flat out all the time, which will end
your problem. If you find this a bit noisy you can always buy a new "quiet
" CPU cooler. Quiet, of course, is a relative term.... so don't expect too
much.
There are lots of way's to do this, you can go to Radio Shack, or Home
Depot ,and buy some quick connect wire splice snap on modules, or
you can buy an adaptor for a couple of dollars which will do this for
you. Go to www.cyberguys.com and do a quick search for item 1480021, which
is a Fan to 4 wire Molex Connector.
Good luck with it!
Rode
The NOSPIN Group
http://freepctech.com
>I just completed a BIOS chip upgrade (failed BIOS flash, had to install a new
>BIOS chip) and noticed a problem with the CPU fan.
>
>When booted, the fan mounted on the CPU (PIII, 500Mhz, Slot 1) kicks in and
>operates as it should. As soon as the OS loads, the CPU fan stops. I have yet
>to observe the fan working while installing the hardware, software, and
>testing
>the machine.
>
>At first, I thought that "maybe" it wasn't needed under a low processor
>load... so I tested my theory by burning a CD to force the processor to
>put its
>brains to work. - an alarm sounded, and I quickly shut down the computer.
>(I did
>set the CPU to shutdown in the BIOS when the temperature reached 140 degrees,
>so I hope I wasn't a total idiot by testing my theory!)
>
>I can't find a setting in the BIOS or the OS (Win2KPro) that controls the CPU
>fan... anyone have any ideas? The fan does work during POST, so I'm assuming
>at this point that it isn't a mechanical failure... I'm thinking it must be a
>BIOS or OS issue.
>Thanks-
>Karen Wasson
PCBUILD maintains hundreds of useful files for download
visit our download web page at:
http://freepctech.com/downloads.shtml
|
