CPU Fans Stop Working when PWM fan connected to OPT_FAN header

[JANSHIM]

I have a dual fan NOCTUA NH-U12S CPU cooler connected to the CPU fan header and this works great. Board is a Maximus V GENE. This morning I added a Cooler Master 120mm PWM chassis fan and connected to the OPT header. When I powered on the PC I noticed only the Cooler Master fan was spinning. I let the OS boot thinking the fans might kick in later but they never did.

But as soon as I unplugged the Cooler Master fan, the Noctua fans started spinning again. Is there a reason this should happen? I now have the CM fan connected to CHA_FAN2 but control is limited.


Jan

[Arne_Saknussemm]

Not 100% sure of this but I think the CPU fan headers are mirrors and electrically linked? and the two different fan types might not like each other..? CPU opt certainly has no separate control and just does what CPU header does...

That pic is confusing by the way... Fan looks to be connected to a header where there is no header...have you got the two noctua fans connected to a Y splitter and then to CPU fan header?