Laptop CPU fan not working

VsYK

Honorable
Nov 23, 2013
8
0
10,510
Hi, I am currently trying to fix an Asus UL30a Laptop. All works great apart from one thing, the CPU fan refuses to spin.

Now, I have purchased 2 replacement fans from 2 different sellers to rule or try to rule out dud fans. Anyways, I don't know if this laptop fires up the cpu fan when it gets too hot or from boot. But I left laptop on for 5 miins without it & it decided to switch itself off so I presume its from boot?

I have tested the 5V & 3V pins & they both give that power. Connected a 5v fan it & it fired it up from boot. Connected one to both yellow, red & again it fired up.

The only thing I cant test is the PWM (blue wire) which is basically the controller for the fan.

It has latest 212 firmware & everything else works great. I even went to the extreme lengths of getting a hold of 2 identical motherboard & DC boards & switched them around & I get exactly the same thing.

Now I'm not 100& sure but how can I test the fans i purchased? I don't have any other hardware that uses the PWM to rule out its not the fans but 2 from separate sellers, both cant be faulty.

Your help would be greatly appreciated.

Thanks in advance!
 
Solution
the fan won't run right away as had to replace a customer's fan & when I did, it did not kick in for a while as the laptop was still somewhat unassembled. even assembled it took a while before kicking in. I think that laptop was an asus too.
was the laptop left open when you connected the new fan to see if it will spin from bootup or when cpu got hot?
 


Yep, I had the both boards connected & keyboard, touchpad & everything else wired up as if it was in the case. I even put it all back in the case just to rule it out with the keyboard not clipped in fully so I can see the fan & still nothing. I didn't leave it until it got hot because I didn't want to risk damaging it as the boards are hard to come by!

Just had a new fan come today, used but from an identical laptop that broke & I was assured it was working so its not the fans. I don't know if this laptop model only fires up the fan if it gets beyond a temp to save battery or not. I've sent a support ticket to Asus & asked them because everything works but it just refuses to spin on 4 different fans all purchased & stated working & New!
 
the fan won't run right away as had to replace a customer's fan & when I did, it did not kick in for a while as the laptop was still somewhat unassembled. even assembled it took a while before kicking in. I think that laptop was an asus too.
 
Solution