It seems that when the modifications were done to this particular chassis, there was an accidental swapping of wire harnesses when reassembling that was causing the team som difficulty. The swap I found was at the ISI Coil Driver Chassis Interface Board, connectors P6 and P9, which would swap the Coarse/Fine 1 & 2 Coil Driver Output signals. The unit was reinstalled and I'm waiting to hear the results of this correction.