Negative voltages

  • Thread starter Thread starter Gilligan Monger
  • Start date Start date
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Gilligan Monger

I've recently built a new Pentium 4 system and have hooked it up to
Motherboard Monitor just to keep an eye on the temps, fans and voltages
whilst it burns in. I notice MBM defaults to displaying your -5v and -12v
lines, and displays mine as running at c. -2.8v and -8.2v. My question is,
are these rails used for anything anymore, and if so why are mine showing
such big variances? Indeed, in what situation does any device require a
negative voltage?

Last question - I know it's possible to monitor your Vcore voltge and Core
1, which is currently reading my memory voltage supply, but does anyone know
of a way to monitor the AGP voltage. I using an Abit IC7 for what it's
worth.

Cheers
 
Somone with more knowledge will probably answer, but in the meantime, I
think MBM makes a guess at each display, and you can go into the settings
and hunt for the proper sensor that matches.

I have one fan it can't display properly at all.

Can't go look at it as I'm booted to a clean install I haven't built up yet.
 
Seeing as you didn't quote the OP [and x-posted, to a totally irrellevent
group I might add (maybe you were not paying attn, as I've done
before...not casting stones)], I'm sure the masses will, totally benefit
(sarcasm). Much less, I'm sure someone will be able to offer a better
answer, when they can't even see the original post. Just an FYI, Ed...not
everyone has 500year retention on their news servers. Some people don't
even have 3 days. Learn to quote. Or, are you too lazy to do such?

www.usenet.org


-
Ed Light stood up, at show-n-tell, and said:
 
Use the program, that came with the motherboard. MBM is not, yet, up to
par with P4 motherboards. I used MBM, for years, with AMD based boards.
They need time to figure out the new P4 boards.

-
Gilligan Monger stood up, at show-n-tell, and said:
 
Gilligan Monger said:
I've recently built a new Pentium 4 system and have hooked it up to
Motherboard Monitor just to keep an eye on the temps, fans and voltages
whilst it burns in. I notice MBM defaults to displaying your -5v and -12v
lines, and displays mine as running at c. -2.8v and -8.2v. My question is,
are these rails used for anything anymore, and if so why are mine showing
such big variances? Indeed, in what situation does any device require a
negative voltage?

Last question - I know it's possible to monitor your Vcore voltge and Core
1, which is currently reading my memory voltage supply, but does anyone know
of a way to monitor the AGP voltage. I using an Abit IC7 for what it's
worth.
Click to expand...

MBM (and Speedfan) frequently misinterpret voltage and temp readings.
Check in the BIOS and compare.
AFAIK -5V is not used by any device, -12V is used by the serial ports
only and as far as they are concerned anything between -5 and -15V will
do.
I don't know of any mobo that monitors the AGP supply line. With all the
oveclocking and overrunning maybe its time the mobo makers considered
it.
 
Gilligan Monger said:
I've recently built a new Pentium 4 system and have hooked it up to
Motherboard Monitor just to keep an eye on the temps, fans and voltages
whilst it burns in. I notice MBM defaults to displaying your -5v and -12v
lines, and displays mine as running at c. -2.8v and -8.2v. My question is,
are these rails used for anything anymore, and if so why are mine showing
such big variances? Indeed, in what situation does any device require a
negative voltage?

Last question - I know it's possible to monitor your Vcore voltge and Core
1, which is currently reading my memory voltage supply, but does anyone know
of a way to monitor the AGP voltage. I using an Abit IC7 for what it's
worth.

Cheers
Click to expand...
As per THG the -5v and -12v aren't used anymore though I found errors with
THG articles. There's a link off MBM5 to take you to the MBM5 forum
website. MBM's author Alex Van Kaam should be able to answer your questions
about voltages.
 
In the latest specs the -5 is optional, while the -12 is usually used
just for serial ports. However, some analog sound uses +/- 12.
 
To clarify RS232 is a bipolar signal. From the specs.

Signal State Voltage Assignments - Voltages of -3v to -25v
with respect to signal ground (pin 7) are considered logic '1'
(the marking condition), whereas voltages of +3v to +25v
are considered logic '0' (the spacing condition). The range
of voltages between -3v and +3v is considered a transition
region for which a signal state is not assigned.

As you can see it requires both + and - voltages. Normally
in PCs +/- 12 volts is used.
 
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