This article explains how to resolve a System Fan (90B) error from appearing when you start up your HP Pavilion G6 Laptop. The full error reads:
The system detected that a cooling fan is not operating correctly
And looks like this:
HP Pavilion G6 System Fan 90B
The error is caused by the system cooling fan not spinning. Notice I said “Not spinning”. The most likely cause is that the fan is stuck or has fell off its spindle. Rarely are any new parts required for this fix but you will need thermal compound paste as you have to remove the heat sink from the processor.
In this example I have used a HP Pavilion G6 but this article is also applicable to many other laptop models as well as the CQ series from HP Compaq.
This procedure should take less than one hour. You do risk damaging the fan but it may be all that is required. More likely you are going to have to take the laptop apart which is described as follows:
Remove memory and memory compartment cover
Disconnect hard drive and remove
Undo screw that secures DVD writer. This makes opening the case easier later
Remove DVD drive. Careful so that plastic does not break on DVD drawer
Pull both cables off wifi card and undo screw. Remove WiFi card
Undo all remaining screws on base of laptop
Turn laptop over and remove keyboard. The arrows point to small clips that hold in keyboard which need pushing back
Undo screws and release ribbon cables
Undo circled screw and disconnect power cable (top right) and other ribbon cables
Remove motherboard from laptop case
Fan is top right of motherboard. Here you can see there is dust. This dust will not be causing the problem though
Turn motherboard over and undo 4 screws that are holding the heat sink and fan to the CPU
Clean thermal paste from heat sink and CPU using paper towel and cleaning solution. Undo two screws to open up fan
Here we can see the build up of dust that stopped the fan from spinning
Clean out all dust using a vacuum cleaner and paint brush. Apply thermal paste to CPU and reassemble in reverse.
All original photos are here please feel free to use them as you wish.