Watch the video that show the electrical connections of the chair
UNSCREW THE NUT OF THE UPHOLSTERY
Unscrew the nut of the upholstery.
Push and lift up the upholstery.
CHECK THE PCB CBC1
Check the eletrical connection of the cable connectors of the chair (security and motor) on the PCB CBC1.
If chair is not balanced, regulate the 8 exagonal screws on the button of the chair.