The document provides instructions for switching a filter cycle jumper position on an M2/M3 control system topside that is displaying incorrectly. It notes that the system should be powered down before changing the jumper, and the battery backup must be reset by shorting J36 for 30 seconds with power off. It includes a table matching Horizon control boards to Balboa topside part numbers and the correct filter jumper position of either A to middle or B to middle.