Measure for a short between Columns 1 and 8. It could be that somehow they have shorted together causing this problem. If you do find them shorted, then remove the lamp matrix plugs from the Driver board and measure again. This way you'll know if it's in the cabinet or on the board.

Hi Owen

Will pull that lamp and report back.

Excuse my ( well stated ) ignorance in regards to most things electronic……….but how do I measure for a short between columns 1 and 8 ???