Matrox G400 and 1.5v
Lennard
i850/i845 specs require the AGP card to run at 1.5v. Now I've been told that
the G400 is compatible at this voltage, however I need to know, do I have to
do anything to the card to get it to run at the voltage or will the card
automatically switch to 1.5v?
Lennard
Michael
It's automatic.
quip
automatic.
succes..quip
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KevinST
not. If the card is not 1.5v then the red LED comes on and you can not
boot the system.
I've just tried the old G400DH I have in the P4B266 and I can't boot
the system !!!! I "think" the 1.5v cards have a loopback between 2
pins - this may be missin gon my old G400DH.
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Richard Hopkins
"KevinST" <kevi...@yahoo.com> wrote in message
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> My new Asus P4B266 has a special LED to show if a AGP card is
> 1.5v or not. If the card is not 1.5v then the red LED comes on and
> you can not boot the system.
Are you sure the LED only serves that one purpose?
> I've just tried the old G400DH I have in the P4B266 and I can't boot
> the system !!!! I "think" the 1.5v cards have a loopback between 2
> pins - this may be missin gon my old G400DH.
Nope, these cards run fine on 1.5v AGP boards. Thus, the reason for your red
LED is elsewhere.
--
Richard Hopkins
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Cardiff, Wales, United Kingdom
"I don't get a fair whack. I don't pursue vendettas or punch people on the
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KevinST
> "KevinST" <kevi...@yahoo.com> wrote in message
> news:e00f84fd.01122...@posting.google.com...
> > My new Asus P4B266 has a special LED to show if a AGP card is
> > 1.5v or not. If the card is not 1.5v then the red LED comes on and
> > you can not boot the system.
>
> Are you sure the LED only serves that one purpose?
If I take my working system with a GeForce2 GTS card, and replace the
GeForce card witt the G400DH then the red LED comes on and I can't
boot. "When I swap the G400DH out and put the GeForce back in - the
red LED is off and I can boot the system.
>
> > I've just tried the old G400DH I have in the P4B266 and I can't boot
> > the system !!!! I "think" the 1.5v cards have a loopback between 2
> > pins - this may be missin gon my old G400DH.
>
> Nope, these cards run fine on 1.5v AGP boards. Thus, the reason for your red
> LED is elsewhere.
I don't doubt that the G400 is 1.5v compatible - but for some reason
the P4B266 is not detecting something on the G400DH that it does on
other 1.5V compatible AGP cards.
It's got to be a passive thing as the MoBo isn't even running when the
red LED is on - no BIOS or anyting - this (apparently) is to stop the
845D chipset and the AGP card from being destroyed.
KevinST
From the AGP interface spec Revision 2 4 May 1998, Section 4.3.4
(ftp://download.intel.com/technology/agp/downloads/agp20.pdf)
"In the Special interface group, TYPEDET# indicates whether the
interface is 1.5v or 3.3v. If TYPEDET# is open (not connected to any
power rail or signal), the interface is 3.3v signalling. If TYPEDET#
is shorted to ground, the interface is 1.5volt."
TYPEDET# is pin 2A
I believe that Pin2A is the 2nd finger from the bracket end of the
board, on the non-component side. This pin (TYPEDET#) is NOT connected
to ground on the G400DH that I have. I have proven this by using a
multimeter to check the resistance between pin 2A and pin 5A, which is
GND.
Visibly, this pin is connected to a PCB track that goes off to a via
hole. This via hole is not connected to anything on the component side
of the board, but as this is a multi-layer board I don't know if it's
connected to any internal layers.
KevinST
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