Solved

Case fan is running way too fast

Posted on 2006-06-14
15
1,016 Views
Last Modified: 2007-11-27
Hi,

I have a Dell Dimension 8400 here. It runs normally, but after a while the case fan in the back (not the power supply fan) will increase speed to what must be its maximum (which is very loud), even though the CPU is very unlikely to be overheating.

Since this only occurs randomly, but once it does it prevails, I tested the power supply using a power supply tester, leaving the 4 pin connector on the mainboard. If I do this, the fan will immediately go to max speed.

We replaced the power supply and the mainboard, and it still does the same thing.

Is it possible that the fan will go to maximum only when the system is on a power supply tester?
What I am trying to find out is if the system will run normally in its normal configuration and only go to max fan speed if put on a power supply tester. Is that possible or likely?

Any other advice to get the fan to stop acting up?

The fan appears to run normally, just fast - it can blow half-way across the room. Once it runs, it stays at a constant speed. It seems like it is only doing what it is "told" by some other component, but since I already replaced everything else...

Could it be the fan itself? I don't know if they have an electronic speed control inside or something or if it's just the motor.

Thanks!
0
Comment
Question by:semmelbroesel
  • 5
  • 3
  • 2
  • +1
15 Comments
 
LVL 69

Expert Comment

by:Callandor
ID: 16905660
Does the fan have an internal temperature sensor, or is it connected to a 3-pin header on the motherboard?  If it's a 3-wire connector, the fan speed may be controlled by the motherboard and the BIOS settings.
0
 

Author Comment

by:semmelbroesel
ID: 16905731
It's a 5 pin plug, but only 4 pins have wires going to them.
0
 
LVL 92

Assisted Solution

by:nobus
nobus earned 83 total points
ID: 16909480
try with another fan first, it can be simply bad.
0
Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
LVL 14

Assisted Solution

by:FriarTuk
FriarTuk earned 83 total points
ID: 16910691
0
 

Author Comment

by:semmelbroesel
ID: 17065216
Sorry, forgot about this one - doing too many things at once, and I haven't had time to go back to the PC.

I think I will try to replace the fan.

Before that, I'd like to ask one more question:

Is it ever normal for the fan to immediately go into screaming noisy speed when you attach a power supply tester to it,  but not when you run the PC normally?
So far we have not heard the problem again after replacing power supply, motherboard and CPU, but it still comes up when we use the power supply tester. So if no one has ever heard of a fan speeding up like that with a power supply tester then I think it should definitely be the fan itself.

Thanks!
0
 
LVL 69

Accepted Solution

by:
Callandor earned 84 total points
ID: 17070303
A power supply tester should not cause the fan to do that.
0
 
LVL 14

Expert Comment

by:FriarTuk
ID: 17074959
did you try the updated bios for a fix - see the dell link i provided.
0
 

Author Comment

by:semmelbroesel
ID: 17087337
I didn't try updating the BIOS since the motherboard was replaced once with one with a lower Revision number. I didn't look at the BIOS version though. I'll ask a co-worker to try it.

Callandor: I didn't think so - thanks for confirming!
0
 

Author Comment

by:semmelbroesel
ID: 17129883
We're pretty busy these days, so I still haven't had a chance to try it. I'll ask my co-workers again who are in the office more often than I am.
0
 
LVL 14

Expert Comment

by:FriarTuk
ID: 17254920
0
 

Author Comment

by:semmelbroesel
ID: 17317424
Agreed with the split.

Sorry I couldn't follow-up anymore (should have at least said something) - the PC is no longer with us...

Thanks for everyone posting and helping out!
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Article by: SHIELD1
The 5 R's 1. Repair 2. Restore 3. Reinstall 4. Remote admin 5. Run away OK so I'm not the most skilled engineer around but I definitely have an abundance of experience: electronic repairs since I was 13 and PC and computer hardware repair…
How can this article save you time AND money?  In just a few minutes you may discover something you didn't know existed that is easy enough for you to fix yourself!
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question