Tonight I swapped in the working CPU board from my Tri Zone (as PIA on both CPU boards is unfortunately not socketed) .  after a logical suggestion from Ken (suspect PIA on CPU board)
Currently I have gone backwards .. now have no score displays or CPU controlled lamps . 
I am thinking this might be a 40 pin interconnector problem ? as 40 pin male on this CPU board is original (as are all the male edge connectors) , the female on the driver board (the board from Firepower) has been replaced.
I tried reseating IJ3 thru IJ7 (display outputs and blanking) on CPU board and 2J4 thru 2J8 (logic power in and lamp driver outputs/power etc ) on driver board but no change.

I also noticed none of the PIA's on either driver board is socketed .
Of course this means all PIA's are also original