Fan stopped working suddenly (90b error code)

[thanosros]

Hello everyone. Suddenly my laptop gave me this error : 90b about its cooling fan.

I have seen in other threads that cleaning might do the trick and make the fan to work again but with no result for my case

Before considering to replace the fan, one thing seems pretty wierd and that is where my question goes:

When i open the case and see the inside of the fan , it kinda tries to spin but stays on position.

When the fan normaly would start working(hd video, high res video game) , instead it does 3-4 spins and stops.

When i unplug it from the motherboard and let it sit for 10-15 seconds and then plug it again , the fan sudenlly works in perfect condition for 2-3 minutes and then it starts to malfunction again.

Any ideas ? Why does this happen? Could it be a software issue instead of a hardware ?

[I have tried all the suggestions offered by other threads(bios update, hard reset etc.)]

[Huffer · Accepted solution]

Only 2 possibilities: 1. the fan itself is bad; or 2. the fan controller on the motherboard is bad. 

You say you have cleaned it so I am ruling out the third possibility that it is clogged by dirt. 

The only way to tell if it is 1. or 2. is to try a new fan. The symptoms are consistent with a fan that is on its last legs. They usually go through a partial function phase before they completely die. 

[thanosros]

Thank you very much for your reply, I ll try to replace the fan. Do you know if I can disassemble it easy from the heatsink or does it need care from a computer technician ? I saw some videos on YouTube and I think that the only "difficult" part is replacing the thermal paste.

[Huffer]

One person's "easy peasy" is another person's nightmare. Hard to assess your skills from here. The thermal paste is actually the easy part. I usually just buy a whole heatsink and fan unit rather than mess with remounting the fan. It is surprisingly hard to get it lined up just right so it does not vibrate and you don't know if you have it correct until it is all back together. 

[thanosros]

Again thanks for your imediate replies. I bought a new fan and replaced it.  Everything looks fine now, no more error code and no more overheating. You were right about the heatsink , but i couldn't find a combo , so i went on changing the fan , with the screws not 100% placed correctly. Till now i have no issues with vibration or noise but i suggest your proposal for everyone else if they can find the heatsink together with the fan. 

Thanks for your time 🙂