244 Table Base Up / Down Function Troubleshooting
Power To The Hand Control
Refer to: Power To The Table for the 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.
Base Up Operation
When the Base 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 Base Up function is removed, the control box supplies 24 VDC to both lower actuators.
The two lower actuators extend and raise the table.
Both actuator motors run until
1.Hand control button is released.
2.Both actuators are fully extended. Internal limit switches are not serviceable.
Base Down Operation
When the Base 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 Base Down function is removed, the control box supplies 24 VDC to both lower actuators.
The two lower actuators retract and lower the table.
Both actuator motors run until
1. Hand control button is released.
2.Both actuators are fully retracted. Internal limit switches are not serviceable.
No Base Up and/or No Base Down. Tilt function does not work
1.Does the Back function work? If YES, Perform Control Box / Lower Actuator Test. If NO, Refer to: Power To The Table
When Base Up or Base Down is selected,
the table tilts up or down
The power cord must be plugged in, and the power switch must be ON (I) during these tests.
Keep the area around the table clear. The table moves when performing Steps 2 thru 5.
1.Remove bottom cover.
2.Press the Base Up button briefly, then release. If both lower actuators extend go to Step 3. If only one lower actuator extends go to Step 4.
3.Press the Base down button briefly, then release. If both lower actuators retract repeat Step 2. If only one lower actuator retracts go to Step 4.
4.Disconnect both lower actuator wires 1 and from the control box wires.
5.Plug non-working actuator into the control box wire for working actuator. Ex. If lower actuator, 2 did not move, plug it into control box wire 1. Press Base Up/ Down button. If actuator works replace the control box. If actuator does not work replace the actuator.
Table drifts down
1.If head-end drifts down replace Lower Actuator (1).
2.If foot-end drifts down replace Lower Actuator (2).
Noisy actuator(s)
The power cord must be plugged in, and the power switch must be ON (I) during these tests.
Keep the area around the table clear. The table moves when performing Steps 2 and 3.
1.Remove bottom cover.
2.Disconnect lower actuator wire (1). Run Base Up and Base Down functions briefly. If actuator (2) makes loud grinding noise replace lower actuator (2). If actuator (2) sounds OK reconnect lower actuator wire (1).
3.Disconnect lower actuator wire (2). Run Base Up and Base Down functions briefly. If actuator (1) makes loud grinding noise replace lower actuator (1). If actuator (1) sounds OK reconnect lower actuator wire (2).
The power cord must be plugged in, and the power switch must be ON (I) during these tests.
Control Box / Lower Actuator Test
1.Remove bottom cover.
2.Unplug back actuator wire (3). Connect lower actuator wire (2) to control box wire (3).
Keep the area around the table clear! The table may move when performing step 3.
3.Press the Back Up button briefly, then release. Press the Back Down button briefly, then release. Does lower actuator move when buttons are pressed? If Yes, lower actuator is OK. If No, replace actuator. If both lower actuators are OK Go to Step 5.
4.Connect lower actuator wire (1) to control box wire (3). Then, repeat Step 3.
5.Reconnect actuator wires 1, 2, and 3 to corresponding control box wires.
6.Perform Signal Voltage Test: Base Function.
Signal Voltage Test: Base 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 Purple wire. Press Base Up button on hand control. Check meter as button is pressed and released.
5.Move red probe to BLUE wire. Press Base Down button on hand control. Check meter as button is pressed and released.
