641 Chair Foot Up / Down Function Troubleshooting
This illustration shows only the components that affect the Foot Up / Down function. Refer to: Foot Up / Down for a detailed description of Foot Up / Down operation.
•Only the wires that affect the Foot Function are shown.
•If Power Light is On, proper voltage is present at PC Board.
• If Power Light is off, refer to Page A-2 for troubleshooting.
Is There Power To The Table?
When voltage is present at the PC board, the power light is illuminated. Refer to: Power To The Table, for description of current flow to the PC board.
Power To Foot / Hand Controls
Circuitry on the PC board supplies 8-10 VAC to the hand / foot control connection ports.
Refer to: Crash Avoidance System for a detailed description of crash position, and the table functions that are disabled.
Foot Up Operation
When the Foot Up function is activated, current flows thru the hand / foot control, back to the PC board. Circuitry on the PC Board supplies approximately 48 VDC to the foot actuator motor.
The actuator motor runs and raises the foot section.
The PC board continuously monitors the Foot Up Limit Switch and the Foot position sensor. If the Foot Up Limit Switch is tripped (open), the Foot Up function will not operate. If the Foot position sensor detects that the foot section has reached its upper limit, the Foot Up function will not operate.
Actuator Motor runs until:
1.Hand / foot control button is released.
2.Foot Up limit switch is tripped.
3.Emergency Stop button is pressed.
4.Position Sensor malfunction.
5.Overcurrent protection tripped.
6.Software time-out limit is reached, approximately 20 seconds.
Foot Down Operation
When the Foot Down function is activated, current flows thru the hand / foot control, back to the PC board. Circuitry on the PC Board supplies approximately 48 VDC to the foot actuator motor.
The actuator motor runs and lowers the foot section.
The PC board continuously monitors the Foot Down limit switch, the Foot position sensor, and the Foot Extension switch. If the Foot Down limit switch is tripped (closed), the Foot Down function will not operate.
If the Foot position sensor detects that the foot section has reached its lower limit, the Foot Down function will not operate. If the Foot Extension switch is not tripped, and the Foot position sensor detects that the table is in a potential crash position, the Foot Down function will not operate*.
Actuator Motor runs until:
1.Hand / foot control button is released.
2.Foot Down limit switch is tripped.
3.Emergency Stop button is pressed.
4.Crash Avoidance System activated*.
5.Position Sensor malfunction.
6.Overcurrent protection tripped.
7.Software time-out limit is reached, approximately 20 seconds
Problem: No Foot Up or Foot Down.
1.Loose / Damaged Wire Connections - Hand/Foot Control, Foot Actuator, and Foot Up/Down Limit Switches
2.Hand / Foot Control Refer to: Hand and Foot Controls
3.Foot Actuator Refer to: Foot Actuator
4.Main PC Board Refer to: Main PC Board
Problem: No Foot Up, Foot Down OK or No Foot Down, Foot Up OK "beeps"
If Foot Down is inoperable, move the foot extension to its stowed position and the chair functions Base /Back / Foot to full Up position and Tilt to full down position. If Foot Down function becomes operable, Refer to: Crash Avoidance System.
1.Check for Loose / Damaged Wire Connections (Hand/Foot Control, Foot Up /Down Limit Switches, Foot Extension Limit Switch)
2.Foot Extension Limit Switch. Switch affects down function only. Refer to: Foot Extension / Limit Switch
3.Hand / Foot Control Refer to: Hand and Foot Controls
4.Main PC Board Refer to: Main PC Board
5. Foot Actuator / Limit Switches Refer to: Foot Actuator / Limit Switches
Problem: Foot drifts down or Noisy operation, Grinding / squeaking
1.Foot Actuator Refer to: Foot Actuator
Problem: Moves slowly and/or Will not lift patient.
1.Did patient exceed 450 lb. weight limit? Inform staff that max. patient weight is 450 lbs. Refer to: Specifications
2.Low voltage to table Required voltage:
| Required Voltage | |
|---|---|
| 115 VAC models | 115 +/_ 10% VAC |
| 230 VAC Models | 230 +/- 10% VAC |
3.Foot Actuator Refer to: Foot Actuator
Problem: Foot Up and/or Foot Down moves briefly, then stops and beeps.
If Foot Down is inoperable, move the Base /Back to full Up position and Tilt to full down position. If Foot Down function becomes operable, Refer to: Crash Avoidance System.
1.Calibrate PC Board Refer to: Main PC Board
2.Check for Loose / Damaged Wire Connections (Foot Position Sensor, Hand/Foot Controls, Foot limit switches, Foot actuator)
3.Foot Position Sensor Refer to: Position Sensors
4.Foot Actuator Refer to: Foot Actuator
Problem: Foot moves past Max. / Min. position.
1.Adjust Foot Limit Switch Bracket. Loosen two bracket screws and reposition bracket assembly. Check for proper operation. Repeat as necessary.
