With the incorporation of a Motor Controller to the Skyjack Vertical Mast and SJIII DC Electric Scissor Lifts, several things are different from the Hydraulic Proportional units. Operationally, the Hydraulic Proportional units control the speed of the functions by varying the flow of oil through the proportional valve. For the Motor Controlled units, the speed of the pump motor is varied to regulate the oil flow.

The joystick controllers used on the Skyjack SJIII Compact and Conventional scissor lifts, the SJ12/16 Mast lifts, and the Rough Terrain scissor lifts have incorporated a change to the enable circuit of the joystick. You may notice this change when you are troubleshooting the machine. Once the enable trigger is squeezed, an internal timer starts running; if a function is not operated within 7 seconds, the enable circuit is shut off and the joystick trigger must be released and depressed again to reset the enable circuit. The 7 second cut-out is used to inhibit tampering with or bypassing the enable switch with tape, a zip tie, or other means.

The joystick controllers used on the Skyjack telescoping (40/45 T & 61/66 T) and the articulating (46/51 AJ & 63 AJ) boom lift models all operate similarly. Whether it is a single or dual function joystick, testing and troubleshooting steps are the same. When the joystick is powered, it shows a neutral signal to the On-board Control Module or OCM. This neutral signal is between 4.2 and 4.8 volts. As the joystick is moved in any direction, this signal changes by either rising toward 8.5 volts maximum, or dropping to .5 volts minimum.

The joystick on our Vertical Mast and Electric Scissor lifts have two outputs. One output is a system voltage output to operate the pump motor, valve coils, and relays. The other output is the speed, or proportional signal. This is a variable output signal relating to the speed desired for the function.