Asus A8N SLi - Power Problem? Defective Borad?

[TaZZeR]

See what you think of this guys.........

I'm aware of the high power demand that the Asus A8N SLi motherboard requires and it seems asus were unaware of the peak load on the 12V rail. Hence the latest bios updates which apparently slow the peak power demand on the PSU and cure about 90% of power related problems with this board. (according to scan and Asus)

However my problem is as follows:

20/12/2004 Got 1 out of a 100 Asus SLi boards that were send to Scan.co.uk
Setup the system and powered up, no problems..... installed windows and few games, SLi worked fine.
But when using the computer again, I noticed that power was not getting to the GFX cards in the PCI-E lanes. This was the same for SLi or single mode. All i got was a flash of the GFX power LED and a slight rotation of the the heatsink fan. From the testing I done, I found that 1in3 times power would get to one GFX card. 1in30 times I would get power to both cards in SLi.

I got onto Scan who stated they were having problems with the board and as a result I RMA'd the GFX cards and the mobo to be sure. Scan did their tests and found that there no power was getting to the GFX cards and that the GFX cards were not faulty.

15/01/2005 Got another board from Chillblast.co.uk and this board behaves in exactly the same way, but worse. I never get power to the GFX cards in single or SLi mode, however many times I try.

1) I have installed 1003 bios update using a PCI card for display, problem persists!
2) I am using a Enermax 600W Dual 12V 18A 17A rail, bought a Tagan single 12V 28A rail to see if this was the PSU that was the problem, problem persists!
3) I have tried single and SLi mode, problem persists!
4) I have taken out CPU, RAM etc... chenged CPU to lower power demand, problem persists.....
5) Cards work ok, tested......
6) All power connectors connected correctly. 4pin molex, 24pin, 4pin ATX and power to PCI-E cards.
7) Check mobo for shorting
8) Cleared CMOS etc as per instructions

This problem seems more than just PSU related, I have eliminated the PSU, bios updated, just seems so fundamental. Simply power is not getting to those cards, but why? they work ok!

Is ayone else getting this problem, I would really need to know if I'm unlucky enough to have two faulty boards or if there is a problem I can reslove?

SYSTEM
---------
Noisetaker 600W dual rail 18A 17A or Tagan 480W single rail 28A
FX-55
XFX 6800GT x 2
Asus A8N SLi Deluxe Mobo
Raptor 74GB
Audigy 2ZS (not conected)
CM stacker Case
Asetek water cooling (not connected)
22" Iiyama Pro 513

 

[FastEddie]

For the purpose of trying to resolve this, could you use the single rail psu (the Tagan 480W single rail 28A) as I'm not sure the bios update corrected the peak power problem = "Hence the latest bios updates which apparently slow the peak power demand on the PSU and cure about 90% of power related problems with this board. (according to scan and Asus)."

Try using the PCI video card just to get into cmos setup PCIPnP and change Initial Display First to PCI-E. I'll be back with an edit, as I've got to reboot and write down the new functions the 1003 bios gives us regarding configuring the PEG link, etc...

 

[TaZZeR]

Using the Tagan atm, no change

Will altering the CMOS have any effect? Problem seems too fundamental, no power to the cards from the second you press the ON switch, just a flash of the LED's. I'm even getting no spin of the heatsink fans.

The cards have there own power input, so why would power stay on?

Dear Mark,
I believe it modifies the boot up sequence and lowers the peak power demand slightly.

Michael Mullen
Technical Support

ASUS UK Ltd
Unit 5
Vermont Place
Michigan Drive
Tongwell
Milton Keynes
MK15 8JA

 

[TaZZeR]

I have noticed the CPU fans spins slowly and then to full speed after about 5 seconds, I guess this should happen.

 

[FastEddie]

Originally posted by: TaZZeR
I have noticed the CPU fans spins slowly and then to full speed after about 5 seconds, I guess this should happen.

That's a normal function.

First, it's going to be a PITA, because you're going to have to use the PCI video card to enter the bios and make these changes, but it's about the only way to troubleshoot this problem to see if it's the board when combined with these particular cards. Also when you are into the cmos setup the next time, disable the full screen logo in the event you can view the POST screen, (if you can get it to come up).

Also, disable all other onboard functions that you aren't using (marvel lan, Silicon SATA ports, etc...).

Seems that the bios functions are the same for the graphics ports. But you can try a few different settings to see if it makes a difference. In cmos setup, Advanced/Peg Link Mode, set PEG Link Mode to Normal instead of Auto, PEG Root Control to Enabled, and PEG Buffer Length to Long. Try these on three successive boots.

 

[FastEddie]

Another consideration. Do you have seperate power connected to the actual cards themselves?

Tried changing the DVI adapters to the second DVI port on the card themselves?

 

[TaZZeR]

Yep, both cards have a 12v 6pin power which is connected, I have tried disconnecting and connecting this plug for various boots, and the same with the EZ, all possible permutations and combinations.

Bios update had no effect, this problem is before the bios can have anything to do with the system?? The very second that ON switch is pressed, flash of power to the GFX cards and that's it

To be honest I have not bothered connecting a monitor, I only did this when I had the PCI card installed to update the bios.
The reason for this, is I know i'm not going to get the display on the DVI out cause the power on the Cards is not shown on. Just get that blip with the power LED and then off...... something is a miss just can see why power only stays on monmentarily, they have their own power! and the PSU has been eliminated as a potential problem.

 

[FastEddie]

Originally posted by: TaZZeR


To be honest I have not bothered connecting a monitor, I only did this when I had the PCI card installed to update the bios.
The reason for this, is I know i'm not going to get the display on the DVI out cause the power on the Cards is not shown on. Just get that blip with the power LED and then off...... something is a miss just can see why power only stays on monmentarily, they have their own power! and the PSU has been eliminated as a potential problem.

I would try them connected to the monitor. They made need the video output signal to stay powered up.

 

[TaZZeR]

No luck

 

[FastEddie]

You tried both DVI outputs on the top card? This is beyond being mysterious. I wonder if another brand of card would work?

 

[TaZZeR]

Tried both outputs on both cards, no power getting to them.......

It's a joke, can get my head around it!

 

[Thorsson]

Have you tried clearing the CMOS, or as it says in the mobo manual, the RTC RAM (page 2-17)?

 

[FastEddie]

Originally posted by: TaZZeR
Tried both outputs on both cards, no power getting to them.......

It's a joke, can get my head around it!

I'd also try setting the board up outside the case, just to see if you have a grounding issue with the PCI-E ports. I know the board is working with the PCI card. What are the odds of getting two boards that have the same problem with the graphic ports? Would have to be astronomical. Sure you don't have an extra standoff under the board that might have slipped your inspection? Alot of cases come setup with standoffs inplace, in a 4-3-3 configuration, where the 4 standoffs run in a line vertically along the back edge of the case. This board only uses 9 standoffs, in a 3-3-3 mounting configuration.

This board didn't come from Scan? I know you could bring it there and have tech try a card on the spot. Wait, the 6800GT's came from Scan--bring them and your board there and see if they can test your board with a 6600GT, (just to see if your board does POST).

 

[imported_slippy]

Are all of your jumpers on the board where they should be, as the manual shows. I think I remember it saying something about where you can mess with jumpers or not, and that the board wouldn't boot or would be damamged.

Maybe a jumper was put in the wrong place at the factory or they forgot one. Look a tthe manual to see where they should be.

Other than that, make sure your selector card has the double side pointed towards your blue pci-e, maybe check that it is all the way in.

Other than that, is your ram and videocard clicked into place.

Other than that, are any of your wires interfering with static sensitive parts on your board, like ram, processor/heatsink, mobo, of graphics cards. I can just imagine some dangling wire in there whose end is making some sort of contact.

Fianlly, for this to happen to two boards is too much of a coincidence. I'm seeing either a serious grounding issue, or some wires are crossed somewhere. It is also possible that you are screwing your boards in too tight when you're installing them. They should not be tight, but they should also not be loose. I could imagine that causing damage in the exact same place each time you tried a board, if that is what you did.

Good luck.

 

[TaZZeR]

Thanks for the advice, I've done what you asked.

I've tried the board on a table, connected to the case, and with and without screws......

I'm just lost.

Your right, it seems too much of a coincidence and I dont know anyone else with a problem like this. Only psoitive thing is scan tested it, with my GFX cards and said it was not getting power - faulty. They tested my GFX cards and found them not to me faulty.

What do you reckon, RMA, get a 3rd? I don't know what kind of fault could do this though?

 

[imported_slippy]

3rd times a charm, they say. Let us know if it works.

 

[imported_slippy]

I was just thinking that the board probably gets some grounding from the I/O shield. Did you use the I/O shield both times?

Maybe Asus just took a serious crap on the UK suppliers.

 

[FastEddie]

Originally posted by: TaZZeR
Thanks for the advice, I've done what you asked.

I've tried the board on a table, connected to the case, and with and without screws......

I'm just lost.

Your right, it seems too much of a coincidence and I dont know anyone else with a problem like this. Only psoitive thing is scan tested it, with my GFX cards and said it was not getting power - faulty. They tested my GFX cards and found them not to me faulty.

What do you reckon, RMA, get a 3rd? I don't know what kind of fault could do this though?

I tend to agree with you. It's obviously the board. The processor and memory are both good. Scan tested the graphics cards and found they were good. Like slippy said--3rd time's got to be the charm.

 

[TaZZeR]

Originally posted by: slippy
I was just thinking that the board probably gets some grounding from the I/O shield. Did you use the I/O shield both times?

Maybe Asus just took a serious crap on the UK suppliers.

Sorry, what is the I/O shield?

 

[imported_slippy]

Well... it is really really a longshot anyways, but the I/O shield is the rectangular piece of aluminum that came with the board, that you put on the hole in the back of your case. I'm sure you have it in there, and I really don't know how much grounding it actually does, but all those tiny pieces of metal are on there for grounding the motherboard to the case I believe.

Like I said, it was a longshot. Just trying to think of things besides the board which may be at fault. If it happens with your 3rd board, then we can certainly say that it is not the board.

 

[FastEddie]

I ment to ask. What adapters are you using for the graphics cards? The PCI-E to molex adapters. I've heard that there are problems with some of them being wired incorrectly is why I ask.

 

[century child]

I saw Thorsson's post on this too but I have my doubts about this as I have seen nothing about this in all the forums I regularly read. I wouldn't spread the rumor around about falsely wired cables just yet until he comes up with something to substantiate it.

 

[FastEddie]

I've seen this eslewhere, and currently have a request for further explanation there as well. Shame to RMA another board that works otherwise, until we get more info on this possible issue.

 

[TaZZeR]

I'm using a DVI-VGA adapter.

However I'm not worried about connecting the GFX cards up yet, as I know I wont get a signal cause the power LED's on the cards don't light, still getting a mere flash.

Strange thing is, my 1st board, would allow power to the cards randomly upon turning on and off the power. Over Christmas, knowing this to be the case I left the computer on for several days knowing that if I turned it off it would be nightmare to get back on. No issues with power when it actually gets to the cards in SLi or single mode. I called Scan.co.uk about this, spoke to their tech head who stated they are aware of this problem, and in 90% of cases a bios update would cure this?

To be honest I dont think they know what the problem is. I suggested the good old power issue, becuase of the dual rail 18A 17A, I was knocked back saying my peak load on one rail would only be 180W and my Eneramx PSU shoulld be fine. They said restting the CMOS would do nothing, unplugging the power would have the same effect. Not believing them I bought the TAGAN 480W 28A rail PSU which made no difference.

I'm thinking how could this be, why would the mobo be stopping continous power to the FGX cards. It's getting to them, but just a flash of the GFX card power LED's. There will be no signal unless they are lit continuously. There is power to the EZ and they have their own external power.

What kind of inital peak load can RAM, one (1) XFX 6800GT, Asus SLi mobo and a FX-55 draw???
This has to be power realted, it ain the PSU's, and there must be people running similar setups to me. I'm with you when you talk about a 2nd faulty motherboard..... what are the chances??

However, when sending the 1st mobo and GFX cards back to scan.co.uk they found tge mobo to work as I've desribed..... faulty?

thanks for the help so far, I have a lot of gear here, and this is driving me mad!

 

[FastEddie]

I was refering to the PCI-E power adapters on the cards themselves.