Problem with new SLI system

[owenPC]

I have put together a new system and can not get the monitor to display anything at all. Here it is ...
DFI LanParty UT nF4 SLI-D Motherboard
AMD Athlon 64 3800+ CPU
WD 160 GB SATA Hard Drive
2GB OCZ Dual Channel memory
2 - XFX 6800 GT PCI Express Video Cards

This is my first go at a dual video card system am i missing something ? I have assem. many other machines before and have at least had the bios come up i am leaning towards a BAD motherboard... what do you think ?

Thanks ahead of time for your help

 

[PanicX]

So you plugged it all in and flip the switch and nothing happens? No LED's no Fans?

If thats the case then I'd say either your power supply is bunk or you've shorted your motherboard in the case somewhere.

Does the PC seem to start up but no video? If so, could be that your power supply is over taxed by your system needs.

 

[owenPC]

It all works but the monitor

I have all the fans working all leds . I get no system start up nothing on monitor .In fact the monitor says check the cable plug in .. like its not plugged in

 

[urbandragon]

I have never used SLI or have ventured into actual troubleshooting it yet... but have you tried using each video card seperately to make sure its not one of the cards.

 

[gamingguy27]

If the monitor does not detect the graphics card then they do not have sufficiant power from the power supply. Also make sure all auxillery power cables are coming from the power suplly with nothing esle plugged into the same line.

 

[owenPC]

I have a 400 watt power supply. The cards came with these pig tail power clips and 2 plug ins . Do i need to plug in power to both plugs and does it matter if they are in the same string ? Thanks again for your help friends i think im on the right track now I ordered a new 600watt Power Supply made just for sli system i will post bad if it worked thanks again ( i had no idea i needed 600w PS for a computer lol )this machine better be good

 

[gamingguy27]

They should be on differnt strings each coming directly to the graphics card from the power supply. Each card should also have its own power lead and a SLI cable going inbetween the cards. The output should also be a double monitor cable with both graphics card plugged into one monitor.