This illustration shows the back limit switches and the three serviceable components of the back actuator. Use the table below to isolate the malfunction.

Problem	Required Action
Motor runs, but makes grinding noise.	Clean / lube actuator threads. Replace actuator if necessary.
Motor runs, but table does not move.	Inspect / replace motor coupler.
Motor does not run.	Perform Limit Switch / PC Board Harness Test.

1.Disconnect harnesses from J6 on main PC board.

2.Place one meter probe on the common (white).

3.Place other probe on the wire corresponding the desired switch (see illustration).

1.Unplug the appropriate limit switch harness.

2.Measure continuity.

Actuator Position	Meter Reading Should Be
Actuator Full Up	White to Black - Open White to Red - Closed
Actuator Full Down	White to Black - Closed White to Red - Open
Actuator Midway Point	White to Black - Closed White to Red - Closed

1.Tag and disconnect back actuator wires (J2 and J3).

2.Place meter probes on actuator wires. Check meter reading.

Meter Reading	Required Action
1 to 10 ohms	Actuator motor OK Perform Motor Ground Test
OL or less than 1 ohms	Replace actuator motor

1.Place one meter probe on actuator wire (J3).

2.Place other meter probe on PC board ground wire.

3.Check meter reading.

4.Repeat steps for J2 wire.

Meter Reading	Required Action
OL or more than 1 mega-ohm	Motor harness OK Perform PC Board Test
Less than 1 ohm	Replace actuator motor

1.Place meter probes on wires at J2 and J3 terminals.

2.Check meter reading while activating Back Up / Back Down function with foot control.

Meter Reading	Required Action
Approximately 48 VDC	PC board OK
0 VDC	Replace PC Board

This illustration shows the back limit switches and the three serviceable components of the back actuator. Use the table below to isolate the malfunction.

Problem	Required Action
Motor runs, but makes grinding noise.	Clean / lube actuator threads. Replace actuator if necessary.
Motor runs, but table does not move.	Inspect / replace motor coupler.
Motor does not run.	Perform Limit Switch / PC Board Harness Test.

1.Disconnect harnesses from J4 and J5 on Motor Control PC board.

2.Place one meter probe on the common wire.

3.Place other probe on the wire corresponding the desired switch (see illustration).

1.Unplug the appropriate limit switch harness.

2.Measure continuity.

Actuator Position	Meter Reading Should Be
Actuator Full Up	White to Black - Open White to Red - Closed
Actuator Full Down	White to Black - Closed White to Red - Open
Actuator Midway Point	White to Black - Closed White to Red - Closed

1.Disconnect power to the chair.

2.Disconnect Back actuator from J1 on PC Board.

3.Set multimeter to Ohms to check resistance.

4.Using a multimeter, place meter probes on actuator wires.

Meter Reading	Required Action
1 to 10 ohms	Actuator motor OK Perform Motor Ground Test
OL or less than 1 ohms	Replace actuator motor

1.Place one meter probe on actuator Black wire (J1).

2.Place other meter probe on PC board ground wire.

3.Check meter reading.

4.Repeat steps for White wire.

Meter Reading	Required Action
OL or more than 1 mega-ohm	Motor harness OK Perform PC Board Test
Less than 1 ohm	Replace actuator motor

1.Place meter probes on Black and White wires at J1 on Motor Control PC board.

2.Check meter reading while activating Back Up / Back Down function with foot control.

Direction	Meter Reading	Required Action
Back Up	Approximately 48 VDC	PC board OK
Any Direction	0 VDC	Replace PC Board
Back Down	Approximately 21 VDC	PC board OK