[SOLVED] 4 pin CPU fan have voltage but doesn't work

[valle.r92]

hi, I have an B85M-DS3H motherboard and suddenly 4 pin CPU fan have stopped working but using a voltimeter it seems to hav 12 v between v+ and gnd, what do you think the problem is?

 

[drea.drechsler]

Defective fan maybe.

 

[valle.r92]

I don't think so, I have tried 4 diferentes fans (I'm using a different from the stock fan) and even doesn't work with stock fan. I also have tried to reset the mbo.

 

[drea.drechsler]

I don't think so, I have tried 4 diferentes fans (I'm using a different from the stock fan) and even doesn't work with stock fan. I also have tried to reset the mbo.

Are they all PWM fans? Those are ones with 4 wires attached to the plug. Try instead a voltage controlled fan (three wires attached) and see if it works.

If it does then maybe the PWM circuit is 'stuck' at 0% or fan off. Never heard of it but hey.