December 2023Table of Contentsviii GS™-3390 • GS™-4390 • GS™-5390 Part No. 1325652GTSection 3 Repair Procedures ..............................................................................................18Introduction ...........................................................................................................18Platform Controls ...............................................................................................201-1 Circuit Board ...................................................................................................20How to Remove the Platform Controls Circuit Board ......................................20Platform Components ........................................................................................212-1 Platform ..........................................................................................................21How to Remove the Platform ..........................................................................212-2 Platform Extension Deck ................................................................................23How to Remove the Platform Extension Deck ................................................23Scissor Components ..........................................................................................243-1 Scissor Assembly, GS-3390...........................................................................25How to Disassemble the Scissor Assembly ....................................................25How to Disassemble a Scissor Arm Pair .........................................................293-2 Scissor Assembly, GS-4390...........................................................................31How to Disassemble the Scissor Assembly ....................................................31How to Disassemble a Scissor Arm Pair .........................................................353-3 Scissor Assembly, GS-5390...........................................................................38How to Disassemble the Scissor Assembly ....................................................38How to Disassemble a Scissor Arm Pair .........................................................433-4 Wear Pads ......................................................................................................44How to Replace the Scissor Arm Wear Pad ...................................................44How to Replace the Chassis Scissor Arm Wear Pads ....................................453-5 Lift Cylinders ...................................................................................................47How to Remove the Lift Cylinder - GS-3390, GS-4390 ..................................47How to Remove the Lift Cylinder - GS-5390 ...................................................493-6 Height Angle Sensor ......................................................................................51How to Replace the Height Angle Sensor .......................................................51