crwdns2934241:0crwdne2934241:0 N Don

crwdns2934249:0crwdne2934249:0:

This logic boards sometimes gets only two diagnostic lights lit (one and two only.)...but there's no video. The screen remains black. I disassembled & then reassembled both & was able to get one to boot fully (fans running a normal speed, hard drive spinning up) but no video and boot up sound. 

crwdns2915684:0crwdne2915684:0:

open