Helllo, 
 
I purchased 2 used EVGA mobo's and I'm having problems with them. I originally sent them back to the original seller a few days ago but for whatever reason the packages bounced back after reaching their state so we're not disputing if it breaks the return policy or not. 
 
First Mobo
 
The first mobo post an FF code. I've looked at the FF guide and video but haven't had any luck. Thus far I've..
- Removed CMOS battery for a few hours
- Switched CMOS batteries from the other board
- Grounded and tested on cardboard
- Ensured that the pins were indeed connected (pushed down with force)
- Pushed down on bios card. I just removed it and will reinstall after a few minutes
etc.
 
I tested it with two CPU's, a brand new EVGA PSU and a used corsair PSU (both 650w), etc. I also cross tested all components by placing them in an Intel DX58SO in which everything starts fine. So I've eliminated them. 
Other things to note are that I currently have a stripped standoff/screw in one of the holes as I haven't yet found my pliers to remove it. Would that potentially cause a short? It also had a strong smell when I first started it last night. I immediately shut it off and after sniffing coffee beans to rest my nose this morning, I smelled different areas and compared it to the Intel. The 24 pin connector emits a strong smell as well as areas around the SATA inputs and RAM inputs. This makes me think that perhaps somebody improperly overclocked it? 
 
Second Mobo
 
The second mobo doesn't show an LED code period. Besides this it seems to be in the best shape of the three mobos. It doesn't emit any strong smells that I can pick up. I've checked for bent pins (did the same with the other mobo) and didn't detect any though I'll probably take pictures for the community to double check if you recommend it. Again, obviously it's not the PSU or anything like that. I'm hoping that it's bent pins but I've resigned myself to the fact that this one is likely gone. But i'm still confused about the one with the FF. 
 
Thanks for any and all advice. If there are details that would help better diagnose please just ask. 

FF means Fully Functional, so something (most likely video card) is not getting all it's requirements to display. I would try it with bare components only, like cpu, 1 ram stick & 1 video card.