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On-board fan controllers #183086 12/24/08 10:53 PM
Joined: Jul 2002
Posts: 8,379
Trumpy Offline OP
Hi All,
A "funny" thing happened here this morning with my desktop computer.
I was having a bit of a play around with the speed controller program for the CPU fan, that came with my mother-board.
I'm not sure what I did, but for some reason, the CPU fan stalled, meanwhile the computers buzzer was letting off a raucous beeping sound, the screen froze and I ended up rebooting.
Once I restarted, it returned to normal, fan was running at it's usual speed.

I won't be mucking around with that program again, even though I hadn't changed the temperature or fan speed settings that much, at least not enough to bring on a thing like that.

What I did find later on, on the Net was a program called SpeedFan, it monitors all you fans speeds, system voltages and temperatures and it's free.
It can be found HERE.

You can buy it too, which means you can do a few other things apart from what the free version does already, but the free version is all I'll ever need.

What I did notice was in the voltages readout, is my +12V is down as far as 8.58V and the -12V is up at -16.97V, is this normal for the voltages to that far out of wack?

Tools for Electricians:
Re: On-board fan controllers [Re: Trumpy] #183151 12/28/08 02:45 PM
Joined: Jul 2004
Posts: 9,569
gfretwell Offline
The plus 12 being that low would concern me. It is what powers fans and media drives. As far as I know just about the only thing they do with minus 12 these days is drive the serial ports and that can be anything from 3 to 30 although some devices do not honor that old standard. My weather station will not talk to a port that is much under +/-12v

Greg Fretwell
Re: On-board fan controllers [Re: Trumpy] #183163 12/28/08 06:01 PM
Joined: Jan 2005
Posts: 354
pdh Offline
I just configure the fan speed in the BIOS using the dynamic temperature ranges. Then without any software or OS intervention, the fan automatically adjusts its speed to the CPU needs. It goes full speed at power on and reset/reboot, and slows down once things are running. One mainboard maker I use (ASRock) slows the fan down gradually. The other (Tyan) slows it down quickly. Both then make speed adjustments as needed to keep the CPU temperature within the specified range.

I have not checked fan voltages on my computers. It is my understanding they use pulse width modulation to control the speed. I don't know what the chopping frequency is. But maybe that chopping is affecting the voltmeter reading.

Re: On-board fan controllers [Re: pdh] #183169 12/28/08 10:45 PM
Joined: Mar 2007
Posts: 404
noderaser Offline
Might not be a bad idea to change out the PSU, they're not too expensive. Just in case the weird voltages are a symptom of bigger (yet undiscovered) problems.

Re: On-board fan controllers [Re: noderaser] #183183 12/29/08 01:39 PM
Joined: Jul 2004
Posts: 9,569
gfretwell Offline
The +12 does not seem to be that well regulated but I always see something in the high 11s.

Greg Fretwell
Re: On-board fan controllers [Re: gfretwell] #183185 12/29/08 01:50 PM
Joined: Sep 2001
Posts: 806
NJwirenut Offline
Are those voltage readings actual measurements taken with a DMM, or just the numbers that the program reports?

I have tried a couple of those "system monitor" programs, including one that Intel included with their own motherboard, and ALL of them had serious "issues" with accurate voltage measurements. Not sure what the measurement system uses as a voltage reference, either.

Measure the supply outputs yourself with a good DMM before swapping out the PSU solely on the results of some piece of software. While you are at it, check each DC supply rail with the meter set for AC, to look for excessive ripple. The first thing to go in those power supplies is the filter capacitors drying up...

Last edited by NJwirenut; 12/29/08 01:54 PM.
Re: On-board fan controllers [Re: NJwirenut] #186632 05/22/09 08:16 AM
Joined: Mar 2005
Posts: 1,213
SteveFehr Offline
If that software wasn't written for your specific motherboard, any readings you get from it are probably wrong. It's often hit-or-miss, with some functions working, but others not. For example, I had to try 3 different programs before I found one that let me monitor my motherboard's temperatures. (It lets me monitor all the voltages, fan speeds, etc, too.)

Re: On-board fan controllers [Re: SteveFehr] #186660 05/23/09 03:03 AM
Joined: Mar 2007
Posts: 404
noderaser Offline
I've had good luck with the "Everest" info tool... Gives you tons of info on hardware, including voltages, fan speeds and temperatures if your motherboard is so equipped. The only computers so far that I haven't been able to get fan speeds/temps from are Dells.

It's primarily a hardware profile tool, but also gives lots of info about the OS.

Last edited by noderaser; 05/23/09 03:04 AM.
Re: On-board fan controllers [Re: noderaser] #192370 02/10/10 09:11 PM
Joined: Jul 2002
Posts: 8,379
Trumpy Offline OP
Just as a question for some of our computer guru's here, what sort of temperature range should you expect from a CPU?
I still have SpeedFan installed here and I think it read as high as 55C (122F), it's as low as 22C (71F) when I start the computer up.

Of course, I guess it depends on the type of CPU and whether the system is over-clocked or not, but what sort of maximum temperature should someone start worrying at?

Mike. wink

Re: On-board fan controllers [Re: Trumpy] #192372 02/10/10 10:38 PM
Joined: Mar 2007
Posts: 404
noderaser Offline
It depends a lot on the CPU; for example, my Athlon64 X2 has a maximum design temperature of 65C while the Core2 Duo in my laptop is designed for 105C. Most chips these days have built-in thermal protection that will scale down operations if you exceed design temperature to prevent sudden death. There are many factors that determine whether said temperature is "ok", but if you're running close to or at the design temp CPU life is probably going to be shortened significantly.

If you have an Intel processor, thermal spec is easy to find:

Note that laptops can be pretty tricky; just because the CPU is ok doesn't mean the heat will play nice with other components. I had a Pentium 4 laptop a while ago that pretty much melted down... All was fine when you started it up cool, but as it warmed up things like USB ports close to the CPU would stop working. The cooling system was sufficient for the CPU itself, but it didn't efficiently evacuate the heat from the laptop--it let too much spread around to other components.

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