Hi folks,
I did a search and came up empty so I'll ask in a new thread.

I have a Dell Dimension desktop unit, about six years old. The other day when I turned it on, it fired up fine but the exhaust fan started in 'high' mode and will not change the speed. Even if the PC is stone cold it does this. It's very loud. I disconnected it to use the PC and 15 minutes later it went into thermal shutdown.
Aside from the nosiy fan, the mouse is moving slow and sometimes the pages won't open quickly in Int. Explorer.
I have windows XP, and the fan is a 1.35 amp brushless fan. I have no idea what triggers the speed settings in this fan, especially since the unit is cold when turned on.

Any suggestions? Need any more info about this PC?
Thanks,
Tom

Motherboard Monitor (http://www.pcworld.com/downloads/file_description/0,fid,7309,00.asp)

There are sensors on certain spots of the motherboard which are used to determine how to control the variable speed fans.

There could be all sorts of things causing your issues, but I'd start out simple. Open up the case and see how much dust you have building up in there. Use compressed air to clean it out, get down on the heat sinks real good, in between the fan blades, etc. Just be sure to hold the fan back as you blow them out, you don't want to overrun the blade cause damage. Also while it's powered up after you do all of that, check all of the fans to ensure they're all working.

Let us know how it goes, that may fix all of your problems.

Thanks guys,

Before I typed this thread, I opened the case (nice hinged flip top design) and removed the fan. I vacuumed the inside of the unit and got out some dust. Not a lot of dust, since I've blown out the unit a couple of times in the last few years. Re-installed the fan afterward.

This morning the fan started on high again, but shut itself off after the full start-up routine. It's runnin quiet now, I'll check the heat buildup in a few minutes and see what may be going on.
I like this Dell unit, it has served me well so far. Will keep you posted.
Thanks again.
Maybe I'll cook a pop-tart on it this morning. :)

Keep in mind as the temperature outside changes and humidity you fans inside may start acting up...Its not 60 in the house anymore...

There are sensors on certain spots of the motherboard which are used to determine how to control the variable speed fans.

Also while it's powered up after you do all of that, check all of the fans to ensure they're all working.

Let us know how it goes, that may fix all of your problems.


Thanks for the reply also. The other fan is still working OK, the one for the hard drive.
The exhaust fan has quit completely now. I have removed it to allow heat to rise up out of the open case. I have about 10 minutes of use time before I'll shut it off to avoid damage.

Keep in mind as the temperature outside changes and humidity you fans inside may start acting up...Its not 60 in the house anymore...

Yes, I agree. This whole problem started when out temps went above 85 degrees outside one day. We still haven't put up the screens or A/C units in the windows yet.
It was cold enough to frost the grass outside last week.
Thanks for your help. I'm gonna look on E-Bay for another fan. Around here we don't have crap for electronics stores locally....
Tom