fan on - slowing shut down

  maltose 13:57 04 Jul 2007

My 2 year old Dell 5150 has only recently started using its internal fan. One unfortunate side effect seems to be that the fan being on considerably slows the shutting down procedure. 5 minute typically with fan on, 20 seconds with fan off. Is there any explanation - or remedy?

  Totally-braindead 14:16 04 Jul 2007

I suspect its dust and the PC is running too hot.
To explain, some PCs keep the cooling fans going for a while when shutting down to make sure the components don't keep warming up when the PC shuts off. It sounds to me like that is what is happening. More dust means the temps will be higher and subsequently the fans will stay on longer till the temperature drops enough to allow shutdown.
I would go inside the PC give it a good clean and make sure all the fans are still running.

  lotvic 14:41 04 Jul 2007

Speaking from my own 'Dell' experiences -
if it is the big fan over the CPU that is revving up its speed it probably means that you have developed a 'hot spot' in the Thermal Paste.
The fan is designed to speed up when the temp is too high.

You need to renew the paste as soon as possible before damage is done.

  maltose 15:47 04 Jul 2007

Thank you Totally-brained and lotvic. I will look inside the PC but please what is thermal paste, where is it in the PC and can a novice renew it?

  lotvic 17:42 04 Jul 2007

Dell 5150
go to click here and download the service manual
go to 'Removing and Installing Parts'
go to 'Heat-Sink Assembly'
this will show you how to get to the heatsink & the processor which will have a layer of grey coloured paste on it. That is the Thermal Paste.

watch these on YouTube
click here=
click here=
click here=
click here=

they will show you how it is done.

  maltose 21:25 04 Jul 2007

Thank you, your pointers are great. I am off on hols for a week tomorrow but on my return I will try removing the dust before going into renewing thermal paste - thank you both very much

  maltose 17:55 11 Jul 2007

some dust removed. Problem does not seem so bad now. Thank you both.

  Diemmess 18:51 11 Jul 2007 and how to deal with it, I think a build up of fine caked dust is the more likely culprit.

Dust can be tenacious and copious in what is normally considered a clean room.

Patience and readiness to spend an hour, is needed for starters.

If there is confidence in a bit of disassembly and reassembly then the job just takes time, not great skill.

Take the fan off.
Unless you really can't get at the heatsink, I suggest you leave it stuck to the CPU with the original paste.

Take a small paintbrush like an artists brush, but a crude cheap one is best becuse it needs to be large enough and stiff enough to do the job.

Now comb out between all the vanes on the heatsink. Fluff and a clay-like buildup of dust can destroy any chance of good air cooling.

Now tackle the fan and sweep each blade clean.
Even a moderate build of dust on this will greatly reduce its aerodynamic efficiency.

Put it all carefully back together and Hey Presto!

Do be careful not to jab the mobo with a slipping screwdiver, the rest is easy.

  Totally-braindead 18:55 11 Jul 2007

maltrose the problem you are/were having is two fold and caused by heat. As I said to prevent overheating some PCs keep running till temps drop enough which is probably why you hav this problem and if theres a lot of dust they won't cool as quick and therefore will take longer to shut down. If the problem is still there, albeit less of a problem than before then you could renew the fans, they do wear and become less efficient, a new case fan for example would be less than a fiver. Other fans are available as well if required.

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