BFG 7800GTX (SLI) & A8N SLI Deluxe No Worky - Need Helpy

[sammy5gs]

Hey Guys...

I recently upgraded my rig which was housing an eVGA 6800GT PCI-express GPU for an SLI Rig housnig two VFG 7800GTX OC GPUs. Well, I uninstalled by 6800GT, uninstalled all of the drivers in Safe Mode via Driver Cleaner. Took my 6800GT out of my rig, switched the EZ-Plug Connector to dual-video card, plug a 4-PIN PSU Adapter to the slot on the mobo that is meant for it, put in my 7800GTXs, plug them into the PSUs, place the SLI Bridge/Connector thingy on top, boot up and I get to BIOS.

In BIOS, I (stupidly I guess now) go into the SLI Configuration of the Bios and specify dual video cards. Upon a save and exit, the computer stops in the middle of POST. I restart and now I do not get an image whatsoever. No signal is going to my GPUs. After checking and re-checking connections, I try to put my old 6800GT back in (switch the ez-plug to single), and same thing - no signal!

I even put in a crappy PCI video card I have laying around, no signal.

I reset CMOS, removed the battery, replaced it and NO JOY.

Any thoughts. At the risk of boring you with all of the components of my rig, here are the critical elements:

AMD 64 FX-55 (stock)
Asus A8N-SLI Deluxe (Bios 1008)
BFG 7800GTX OC (trying to run SLI) - from eVGA 6800GT PCi-ex
Corsair XMS 2GB (1GBx2) DDR400
PC Power & Cooling 510 Deluxe PSU / Thermaltake PurePower 420
WD Raptor 74GB HDD (SATA) / Samsung 80GB HDD (SATA)

Well, any thoughts would be greatly appreciated. Sorry for the length.

[Jcollins82]

Well, that's unsettling. I don't suppose you have another 939 system laying around that you can try and test your parts out in individually, do you?

[sammy5gs]

Negative, ghost rider.

[bazx]

well from what you are saying it is not the gfx that is the problem

i would strip down the rig to just 1xgfx 1xram then change the ram around

but to me i would want to check out the psu

[Jcollins82]

Do the fans turn on? Do you get any beep codes or anything?

How long did you leave the battery out?

It sounds to me like the motherboard may have took a dive.

My suggestion is find a friend with another 939 motherboard around and test your components or RMA the board you have.

[MadInsane]

Hey, do you need the SAME EXACT cards when your running sli? Does it have to be the same manufacturer too?

[consumer9000]

Yes, you generally cannot mix manufacturers, even if the boards are "reference" design parts.

As for Sammy's problems, it sounds like something got fragged during the transfusion. I'm assuming everything else looks ok and that you are using identical boards etc. Is the PSU still any good? If you aren't getting anything from an Asus board, which is rare short of cooking the bios, you might consider trying another PSU, as dual 7800's present a monumental load. :bang head
Good luck, and nice system - once you get it up and running that is. ;)

[Jcollins82]

I doubt it's his power supply. Those PSUs are top notch. Though I suppose anything's worth a shot at this point.