Laptop fan not running normally?

I removed my laptop today to get rid of the dust, I also cleaned the fan and when I was done and turning on the laptop the fan didn't work properly

He walked like this: wuhh wuhh wuhh

So short quiet then loud again then quiet then loud again and that quickly and all the time

Where can I lie the wrong way maybe I attached the cable to the mainboard incorrectly or is there any screw missing? I don't know, please help me

By unscrewing and repositioning the laptop, you can no longer pull the warranty.

But let's first look at the problem, obviously it just doesn't work properly. Please check if it is stuck inside enough and if you see common things in the fans. Are usually the same. (For orientation)

You may have damaged the ball bearing but this is quite unusual. What does the bios say?

Nobody can tell you here what might have been screwed up or assembled incorrectly… You need pictures etc.

What you can do: The Repair Cafes will open again soon! You can certainly be helped there. The fans are, if they are touched a bit hard, something like this!

The laptop was from 2011 anyway and btw it turned out that the fan from the connector was off so a cabriolet was loose and when I pulled it out it broke I order a look obs klapot