No LED3, No Chime. Fan runs. Replaced Logic board. Now what?

I have diagnostic LED 1 and LED 2 coming on but no LED 3. I have replaced the logic board. All capacitors look great. When i press power, the computer comes on, light comes on, no video and NO CHIME at all. After 30 seconds, the fans come on.

If the board is okay, what else is wrong? Why aren't the LCD and the Logic Board communicating? What connections do i check? What else can I replace?

This unit was working fine until I decided to replace the hard drive. I have the original hard drive back in place, but still no go. Replacing the hard drive involves removing the fan cover. I didn't touch anything else during this replacement, exempt the hard drive sensor cable (which i have confirmed is seated properly). The video cable is very close to the hard drive and fans, so maybe this cable has issues? To check that connection I would need to disassemble the rest of the computer.

When I replaced the logic board i notice that the mid-inverter connection seems wiggly from the unit, not at the connection.

I think it's strange that I have had three boards now with no capacitor issues fail to light the 3rd diagnostic light (no video). Can all these boards have bad Video Cards? Perhaps just moving them around causes the card's connections to desolder? Is that possible?