Fans keep on spinning after shutdown

[MicroDon]

Guys, I am having a problem with my computer that I have not seen or listen before. I have installed the Windows XP into my computer and when I go to start and turn off the computer then it lets the computer to shut down without any problem but the fan keeps on spinning without any reason. They keep on spinning about 2 to 3 minutes and then it shuts down that. If I use a rocker switch with the power supply then it stops spinning normally as it should do. I am using the old Pentium 4 Albatron PX915P. It is already having many problems but this is what something new. I am not able to figure out that whether it is a power supply issue or what. Please help.

[samar69]

I would like to ask you one thing that when the last time you cleaned your PC. These problems may be because of the dusting on your computer. If your computer has a lot of dust in it then also it may create such side effect to the computer. Open your computer and clean the dust softly. You can also use any cleaner for the computer available in the market. Remove the connection of the fan to power supplier and reconnect that properly.

[PWallace]

I am agreeing that the dust can do these things to the computer. I frequently keep my computer quite clean however your proposal was worth a try. I am also having the similar problem with mine and to solve that I puff the dust away of the power supply furthermore switched on the computer and then switched it off with the front panel on/off button. After doing that also the problem was not gone. I am using Antec SL350 power supply and I think that it is problem with the power supply. Can you tell me that how can I check that?

[Howitzer]

You are right that it is issue with the power supplier that you are using. To check that, you should take your power supplier out and check that with any other computer and if it is possible then try to connect any other working power supply to your computer and see whether that is working or not. If that is working that this will ensure that the problem is with the power supplier. I don’t know that it is getting repaired or not but it .will be better idea to implement a new power supplier to your computer. I hope this will help you. Thank you.

[pddaugusto]

There are some power suppliers which allow fan power cut off after some time. This is so that it is able to cool the critical components for your computers. There are many semiconductors which raises its temperature even after the power is cut off. The time for is may be fixed to few seconds or it may depends on the heat sensor value in the computer. It will keep running so that critical devices drop their temperature below some threshold.

[Erubiel]

I think that there may be some obstinate particles which are there below the PCB in the PSU. You may also know that it is the most complicated places to make dist free from outside. There is one more possibility that the capacitors have the residual charge which is the reason behind spinning the fan.