Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
Paul wrote:
> In article <4303f5b6@duster.adelaide.on.net>, wilgo02@NOSPAMyahoo.com.au wrote:
>
>
>>Hi,
>>I have recently upgraded the CPU on my Asus P4S8X-X to an Intel 3.06
>>(Northwood) processor. I have 1 Gig of PC 2700 Ram in 2 slots.
>>I am using an Asus V9280 video card (Nvidia Ti4200).
>>I have recently (since upgrading the CPU) been getting voltage warnings
>>from Asus Smart Doctor (monitoring the video card). Very recently the
>>display drops from 1024x768 to something less than 640x480. I'm having
>>to power off and restart to get things going again.
>>
>>Do you think the motherboard is delivering unstable power to the video
>>card? if so, should I get a new motherboard. Same one again? or what
>>would you recommend, so that I could reuse RAM, CPU, video, etc components?
>>
>>Any help appreciated.
>>Gordon
>
>
> AGP 2.0 spec (Vddq pins carry either 3.3 or 1.5V, depending on
> which spec the card meets)
>
> Vddq1.5 I/O Supply Voltage IMAX = 8.0A 1.425 1.575V (average currents <2A)
> Vddq3.3 I/O Supply Voltage IMAX = 8.0A 3.15 3.45V (average currents <2A)
> VCC3.3 3.3V Power Supply IMAX = 6.0A 3.15 3.45V
> VCC5 5V Power Supply IMAX = 2.0A 4.75 5.25V
> VCC12 12V Power Supply IMAX = 1.0A 11.4 12.6 V
>
> AGP 3.0 spec
>
> Vddq1.5 I/O Supply Voltage IMAX = 2.0A 1.425 1.575 V (1.0 amp average VDDQ)
> VCC3.3 3.3V Power Supply IMAX = 6.0A 3.15 3.45 V
> 3.3VAUX 3.3V Aux IMAX = 0.375A 3.15 3.45 V
> VCC5 5V Power Supply IMAX = 2.0A 4.75 5.25 V
> VCC12 12V Power Supply IMAX = 1.0A 11.4 12.6 V
>
> First off, you should have mentioned which voltage was out of
> spec in Smart Doctor, and by how much. Another thing you could
> do, is fire up Asus Probe and get a readout of the 3.3V, 5V, and
> 12V that come from the PSU.
>
> Your new processor draws more current from +12V. On the old
> power supplies, the entire primary side moves up and down, in
> response to the load. The output voltages are established by
> the turns ratio of the multiple secondary windings on the
> output transformer. What this would normally mean, is if you
> tug on +12V (more load), the voltage on +12V will fall, but
> you will also get to see the +3.3V and the +5V rise. This is
> a very handy trend, because when someone reports a problem in
> this group, you can use the voltage trends to identify which
> output on the ATX PSU has suddenly gotten an extra load.
>
> To fix a voltage problem, there are several possible problems
> and fixes:
>
> 1) The PSU could be inadequate for the current load being placed
> on it. I recommend 12V@15A minimum for a P4 system with just
> the basic components. There are web sites that allow a more
> detailed calculation (http://takaman.jp/D/?english but correct
> the overcurrent for disk drives, as the numbers shown are at
> spinup. Your disk manufacturer has the exact numbers, or use
> 12V@0.5A and 5V@1A for a modern, idling disk drive).
>
> 2) The PSU could be sick. Wavering voltages, or complaints
> from Asus Probe about more than +/- 5% variation from
> normal might be your first clue. You might even get a burning
> smell just before it fails.
>
> 3) The ATX 20 pin power connector could be making bad contact
> with the motherboard. There was one Asus motherboard, where
> a bad batch of connectors did not make good contact with any
> ATX supply that was plugged in. The ATX 20 pin should be pushed
> into place, until the latch engages. The latch is there to make
> sure it doesn't work itself loose. If the ATX 20 pin is allowed
> to work loose, the pins heat up due to the partial contact,
> they oxidize, and are permanently crippled. A low motherboard
> power reading at this point, requires connector replacement to
> permanently fix the problem. No amount of bandaid solutions will
> work for more than a short time.
>
> 4) A partial short could be developing within the motherboard PCB.
> This is uncommon. Also, a standoff in the wrong place, could
> touch a copper power track on the bottom of the motherboard.
> The "solder blob" problem on the P4C800 was another example
> of a partial short affecting operation. This only affected
> the initial production run.
>
> So, get out Asus Probe or MBM5 and check the main voltages. With
> the computer unplugged, pull the 20 pin connector and reseat it.
> Check the plastic for signs of heat or melting. Make sure the latch
> is fully seated. Post back what you find when reading both the
> Smart Doctor screen and Asus Probe at the same time.
>
> With some luck, all this will take is a power supply with a few
> more amps on +12V.
>
> Paul
I haven't had any errors today. However here are my current PC probe and
Smart Doctor readings:
PC Probe:
12 Volt = 12.2 +- .04 (does fluctuate)
5 volt = 5.134 (constant)
3.3 volt= 3.14 +- .02 (fluctuates a little bit only)
Vcore = 1.616 (constant)
The video card is an AGP 3 card.
Smart Doctor:
Vcc = 3.04 v
Vcore = 1.68 v
AGP = 1.50 v
From memory I think the error was Vcc going up to (maybe even over) 4
volts.
I'm going out today, anyway, and getting a new 500w PSU.
cheers
Gordon
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