647 Chair Base Up / Down Function Troubleshooting
This illustration shows only the components that affect the Base Up / Down function. A detailed description of Base Up / Down operation appears below.
•If power light is OFF: Refer to: Power to the Chair for troubleshooting.
•If power light is ON: Proper voltage is present at PC board.
•Black and white wires supply 48-54 VAC to power circuitry for the Base and Back actuators.
On models with a rotational base, the main system transformer connections are supplied thru the Rotational Base PC board, not shown.
Is there power to the chair?
When voltage is present at the PC board, the power light is illuminated.
Refer to: Power to the Chair for a description of the current flow to the PC board.
Power to Foot Control / Touch Pads
Circuitry on the PC board supplies 8-10 VAC to the foot control and touch pads.
Base Up Operation
When the Base Up function is activated, current flows thru the foot control / touch pads to the main PC board. Circuitry on the main PC board supplies approximately 48 VDC to the base actuator motor.
The actuator motor runs and raises the chair.
The main PC board continuously monitors the Base Up limit switch and the base position sensor.
If the Base Up limit switch is tripped, open, the Base Up function will not operate.
If the base position sensor detects that the chair has reached its upper limit, the Base Up function will not operate.
Actuator motor runs until
1.Foot control / touch pad button is released.
2.Base Up limit switch is tripped.
3.Emergency Stop button is pressed.
4.Position sensor detects upper limit.
5.Overcurrent protection tripped .
6.Software timeout is reached, 25 seconds.
Base Down Operation
When the Base Down function is activated, current flows thru the foot control / touch pads to the main PC board. Circuitry on the main PC board supplies approximately 48 VDC to the base actuator motor.
The actuator motor runs and lowers the chair.
The main PC board continuously monitors the base down limit switch and the base position sensor.
If the base down limit switch is tripped, open, the Base Down function will not operate.
If the base position sensor detects that the chair is in a potential crash position, or that the base has reached its lower limit, the Base Down function will not operate.
Actuator motor runs until:
1.Foot control / touch pad button is released.
2.Base Down limit switch is tripped.
3.Crash Avoidance System activated.
4.Emergency Stop button is pressed.
5.Position sensor detects lower limit.
6.Overcurrent protection tripped
7.Software timeout is reached, 25 seconds.
Refer to: Crash Avoidance System for a detailed description of crash position, and the functions that are disabled.
