At the MPE: Set DIP switch 4 to ON (up) to enable Dimmer Doubling for all dimmer modules in the rack. See the MPE User's Manual for DIP switch location. Note: It is required that all circuits be connected to a Dimmer Doubler running ETC Source Fours with a 77V HPL. Caution!! Setting DIP switch 4 sets ALL dimmers in the rack to Dimmer Doubled (Multiplexed). Bringing up DMX512 address 1 will bring up dimmer 1A, resulting in only one half of the sine wave to be output. WARNING!! Running motors, transformers or ballasts on one half of the sine wave can cause damage to the device being powered.