The Skyjack full-size rough terrain scissor lift models 8831/8841 and 9250 offer single or dual hydraulic extension decks as an option. These optional hydraulically powered decks extend and retract using a cylinder and hydraulic power pack mounted under the platform and operated from a small control box located on the main platform. When the key/selector switch on the main control box is positioned in the LIFT mode, the power extend deck circuit is enabled, allowing power extension deck operation.
The deck extension cylinder is a single acting cylinder mounted under the platform and connected to the main and extension decks. The hydraulic power unit is a self-contained motor/tank/pump and valve assembly mounted under the main deck. Power for the pump motor is taken from the main battery in the base cabinet and that 12 volts is sent to the power unit’s solenoid from a contactor near the main battery. Power connections for the circuit are found at a small circuit card near the power unit under the platform.
As with any extendable platform, keeping the main platform floor and the extendable deck clean and clear of debris will ensure the deck can move in and out freely. If you experience a problem with the deck extending or retracting, inspect the area for debris and any damaged or loose parts which may impede the deck movement. Any bent platform structure on the main and extension platform will prevent the proper operation of the deck. Consult the correct manual for the serial number of the machine you are working on for specific electrical and hydraulic circuit information when troubleshooting the function.
If you need technical assistance with this feature or have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com.
TECH TIDBIT
When testing electrical circuits, we suggest testing the circuit with system voltage (operating the function) rather than performing a continuity test. The reason for this is that most bad connections or components can support or carry the power of the 9-volt battery in your volt meter; but when system voltage is applied to the circuit the connection fails. Therefore, testing using continuity will likely give you an invalid and inaccurate test result which will have you chasing your tail instead of making progress to find the cause of the problem.
