Overriding PC no boot without CPU fan

40974111 · Post by **40974111** » Mon Jun 08, 2009 4:02 am

My motherboard has a lovely fail safe that prevents the PC from booting if there is no CPU fan detected. The CPU fan header is the typical PWM header. How can I override this fail safe?

philje123 · Post by **philje123** » Mon Jun 08, 2009 4:39 am

I had this while working on a friends old pc.

The way I got round it was to clear the cmos with the motherboard header and then turn it on and go straight into the bios and disable the fan speed warning then it would boot properly.

It would basically turn on once with everything reset then if you tried turning off and on again it wouldn't do it until you cleared the cmos and changed the setting in the bios.

Hope that helps.

Phil

jhhoffma · Post by **jhhoffma** » Mon Jun 08, 2009 6:18 am

If the BIOS just stop with a CPU fan error, all you need to do is disable "HALT ON ERROR" or the similar setting in your BIOS.

rei · Post by **rei** » Mon Jun 08, 2009 8:44 am

depending on your mobo bios, you can tell it to ignore the fan sensor. in my asus p5ql-em i do this since i control the cpu fan from the fan controller in the 5.25" bay.