Can you swap back to the old lamp board just to confirm that the new board is the issue?
If that isn't the problem:
Try resetting all the audits. Step through the diagnostic tests (with button on the inside of coin door) and hit the reset button (on MPU board) for each audit to reset each value.)
Check to make sure all boards are well grounded to the backbox and that the ground braid is connected.
Then I guess you can re-seat connectors (one at a time, with game off) then turn on to see if its a connector issue.
Question: Has this got the original Rom Board right above the knocker? If so, probably lots of cracked solder joints that will need to be re-flowed on that board.
Additional Question: I saw that you have another thread about having NVRAM and a battery connected at same time? Was that on this machine? If so, maybe start with resetting those audits...