631 Chair Back up / down Function Troubleshooting
This illustration shows only the components that affect the Back up / down function.
Power to Foot / Hand Control
115 VAC is supplied thru the two primary fuses F1 and F2 on the Power Supply PC Board.
The Power Toroid reduces the line voltage to 25 VAC.
The Power Supply PC Board reduces the 25 VAC and supplies 12 VDC to the foot / hand control.
Back Up Operation
When the Back Up function is activated, the foot / hand control sends a command to the Machine Control PC Board. The Machine Control PC Board relays the command to the Power Supply PC Board.
+ 24 VDC is supplied thru fuse F3 and - 24 VDC is supplied thru fuse F4 on the Power Supply PC Board to the Motor Control Hub PC Board.
The Motor Control Hub PC Board supplies a commutation sequence to the back actuator DC motor. F3 fuse on the Motor Control Hub PC Board protects the back actuator motor.
The actuator motor runs and raises the back section.
Actuator motor runs until:
1.Foot / Hand control button is released.
2.Back Up limit switch is tripped.
3.Stop button is pressed.
4.Overcurrent protection tripped.
5.Overtravel limit switch is tripped.
Back Down Operation
When the Back Down function is activated, the foot / hand control sends a command to the Machine Control PC Board. The Machine Control PC Board relays the command to the Power Supply PC Board.
+ 24 VDC is supplied thru fuse (F3) and - 24 VDC is supplied thru fuse (F4) on the Power Supply PC Board to the Motor Control Hub PC Board.
The Motor Control Hub PC Board supplies a commutation sequence to the back actuator DC motor. F3 fuse on the Motor Control Hub PC Board protects the back actuator motor.
The actuator motor runs and lowers the back section.
Actuator motor runs until:
1.Foot / Hand control button is released.
2.Back Down limit switch is tripped.
3.Active Sensing Technology® activated.
4.Stop button is pressed.
5.Overcurrent protection tripped.
6.Overtravel limit switch is tripped.
