244 Table Back Up / Down Function Troubleshooting
Power To The Hand Control
Refer to:Power To The Table for description of current flow to the hand control.
Signal Voltage
The hand control continuously supplies signal voltage approximately 5 VDC to the control box thru separate wires for each function.
Back Up Operation
When the Back Up button is pressed, the circuit for this function opens, stopping the flow of signal voltage to the control box. When the signal voltage for the Back Up function is removed, the control box supplies 24 VDC to the back actuator. The back actuator extends, raising the back section.
Back actuator motor runs until
1.Hand control button is released.
2.Back actuator is fully extended. Internal limit switch is not serviceable.
Back Down Operation
When the Back Down button is pressed, the circuit for this function opens, stopping the flow of signal voltage to the control box. When the signal voltage for the Back Down function is removed, the control box supplies 24 VDC to the back actuator. The back actuator retracts, lowering the back section.
Back actuator motor runs until
1.Hand control button is released.
2.Back actuator is fully retracted. Internal limit switch is not serviceable.
The power cord must be plugged in, and the power switch must be ON (I) during these tests.
No Back Up and/or Back Down function. Base and Tilt functions OK
1.Remove bottom cover.
2.Unplug two lower actuator wires 1 and 2. Connect back actuator wire (3) to control box wire (2).
Keep the area around the table clear! The table may move when performing this step.
3.Press the Base Up button briefly, then release. Press the Base Down button briefly, then release. If back actuator moves Go to Step 4. If back actuator does not move Perform Wire Harness Extension Test.
4.Reconnect actuator wires 1, 2, and 3 to corresponding control box wires.
5.Perform Signal Voltage Test: Back Function.
Back section drifts down or noisy actuator
•If back section drifts down replace back actuator.
•If back actuator makes loud grinding noise replace back actuator.
Signal Voltage Test: Back Function
Meter should indicate approximately 5 VDC, when hand control button is released. If not, Refer to: Limit Switch Circuit Test.
1.Remove bottom cover. Remove power inlet housing cover.
2.Set meter to read DC voltage.
When specified hand control button is pressed, does voltage drop to approximately 0.7 VDC? If Yes, replace control box. If No, replace hand control.
3.Place black probe on Grey wire (common).
4.Place red probe on yellow wire. Press Back Down button on hand control. Check meter as button is pressed and released.
5.Move red probe to brown wire. Press Back Up button on hand control. Check meter as button is pressed and released.
Wire Harness Extension Test
Early models do not have a removable channel cover. To access the electrical connector, remove the seat section cover. Refer to: Seat Section Cover.
1.On models with removable channel cover, remove four screws and channel cover. Disconnect back actuator wire from the electrical connector.
2.Route back actuator wire to control box.
3.Disconnect wire harness extension (3) from control box wire (3).
4.Connect back actuator wire to control box wire (3).
5.Press Back Up/ Down button. If actuator works replace the wire harness extension. If actuator does not work replace the back actuator.
