Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <ss5bf01egc0sletvj8gu2eebcqo0lc0vq0@4ax.com>, Eli
<nobody@anywhere.com> wrote:
> On Wed, 14 Jul 2004 03:20:45 -0400, nospam@needed.com (Paul) wrote:
>
> >In article <l789f0ppol6asmkbst7smts512pfslnkc8@4ax.com>, Eli
> ><nobody@anywhere.com> wrote:
> >
> >> I installed Motherboard Monitor 5 on a new system with a P4C800-E
> >> Deluxe and running Windows XP Pro. The only real hitch was that MBM
> >> displayed +12V readings of about 12.6V to 12.7V while Asus PC Probe
> >> showed 11.98V to 12.04V. Assuming that Asus PC Probe was probably
> >> "more" correct, I adjusted a multiplier in MBM so that it now displays
> >> the same voltage. All other reading are identical in the two
> >> programs.
> >>
> >> One oddity, though, is that MBM shows a third temperature sensor that
> >> Asus Probe does not. Depending on the exact sensor source selected,
> >> the temp reading is either a negative number or about 127 degrees C.
> >> Is that a real temperature sensor, or does the onboard sensor chip
> >> have the capability of monitoring three temperatures, but the P4C800-E
> >> only uses two of them?
> >
> >There is a 2 pin header on the board called TRPWR. It is expecting
> >an NTC thermistor of resistance 10K ohms at 25C (beta = 3435K). At
> >this very moment, if you were to go to Radio Shack, and get a 10K
> >ohm fixed resistor (doesn't matter whether it is 1/4W or 1/8W, 5%
> >is close enough). Place the resistor across the two pins on the
> >TRPWR header. When you do, you should find MBM5 indicating 25C on
> >the third sensor. That would prove you are seeing TRPWR.
> >
> >An alternative experiment, is to touch the two pins on that header
> >with your fingers. The resistance of your fingers might be enough
> >to register. You may see the readout in MBM5 change when you touch
> >the TRPWR header.
> >
> >There is some raw data here, for a typical thermistor. Using your
> >fingers would give a resistance of perhaps a couple hundred K ohms.
> >The MBM5 value should respond by reading -42C or so (if the third
> >sensor if TRPWR). It all depends on how conductive your fingers are,
> >and there is a good deal of variation between humans.
> >
>
>http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=nospam-1901031939470001%40192.168.1.177
> >
> >Just a guess,
> > Paul
>
> Paul,
>
> Thanks, I'll try that little experiment. Any idea where to get such a
> 10K ohm NTC thermistor, preferably with connector attached? It would
> be nice to use it to read ambient case temperature away from the
> motherboard. Right now it reads -48C with nothing across it.
>
> Jim
The cable was referred to as Asus P2T. But I doubt Asus still makes
them.
There are some thermal probes floating around the net, like this one:
http://www.com-tra.de/shop/de_DE/produkt/id_is_1234
I think devices with that kind of black wire, came with the Digidoc5
fan controller. When vendors list them for sale, there are no specs
listed, so you cannot verify whether R at 25C is 10K ohms, and the
beta is 3435K. Beta defines the curvature of the temp versus resistance
curve, and the software reading the sensor and the hardware have to
agree on that parameter. Since most Windows software isn't going to
allow you to program those constants, that is why you need to search
for a particular set of values for the sensor.
I found some parts on Digikey, but they don't have wires on them.
Look for P12011CT-ND and P12007CT-ND on this page. The latter of
the two is pretty tiny:
http://dkc3.digikey.com/PDF/T042/0934.pdf
Bigfootcomputers.com has the same kind of cable as shown in the
com-tra.de link above. But doesn't list the beta value either.
And, at $9.50 CDN each, overpriced. The thermistor itself is
probably worth in the $0.50 to $1.00 range for small quantities.
http://www.bigfootcomputers.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=2399CGTD&Category_Code=
http://www.bigfootcomputers.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=2400CGTD&Category_Code=
Paul
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