Fans connected to MB always on. quick help please

[jeff77789]

The CPU, graphics and another 3pin fan were connected to my motherboard (Biostar H61 MGC) for my new build. After I shut the machine off, all but the graphics fan were still spinning. After i had switched the power switch on the psu to off and had unplugged it, the fans were still spinning for about 2 minutes afterwards. This wasnt a full speed spinning but minimum rpms. Worried that the small battery on the mb was powering these fans and power would soon run out, i plugged it back in and powered on once again.


do you guys have any clue as to why this is happening?

 

[jeff77789]

I switched the 3-pin fan plugged into the Motherboard into a molex and the same symptom....the fan kept going after it was unplugged from the wall. The CPU fan and gpu fan has stopped spinning upon shutdown.

My power supply is a cooler master elite 500w

 

[scottiemedic]

When you shut down the power supply, there is residual energy for lack of easier terms still present in the PSU that could be supplying minimal power.
OR
The fans have great bearings in them and takes them that long to actually stop spinning.
TEST
Turn it back on, run it for a few minutes then power down and put your finger on the center hub of one of the spinning fans to stop it. When you release your finger, if it starts spinning again, it's electricity, if it stays stopped, it's just the spin down time for the fan...

 

[jeff77789]

When you shut down the power supply, there is residual energy for lack of easier terms still present in the PSU that could be supplying minimal power.
OR
The fans have great bearings in them and takes them that long to actually stop spinning.
TEST
Turn it back on, run it for a few minutes then power down and put your finger on the center hub of one of the spinning fans to stop it. When you release your finger, if it starts spinning again, it's electricity, if it stays stopped, it's just the spin down time for the fan...

I actually figured it out. I stopped the fan and it still ran but i decided to move the computer so i had to unplug the HDMI cable from the back end and that was actually feeding enough power to the cpu and the one case fan to keep them on

 

[jeff77789]

Best answer selected by jeff77789.

 

[nikorr]

This topic has been closed by Nikorr