647 Chair Troubleshooting Chart

No functions will operate

Symptom	Probable Cause	Check	Correction
Power light is OFF.	Facility supply voltage.	Power cord connections and facility circuit breaker.	Secure power cord connections. Reset circuit breaker if necessary.
	Primary fuse(s) blown.	Inspect fuses.	Replace faulty fuse(s).
	Main system transformer	Wire connections between power inlet and main PC board.	Secure loose connections. If connections are OK, test the transformer. Main System Transformer
	Main system transformer	Models with Rotational Base: Wire connections between rotational base PC board and transformer.	Secure loose connections. If connections are OK, perform EMI Filter Board Test. Rotational Base Brake System.
	Main PC board	If main system transformer is OK	Replace main PC board.
Power light is ON.	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
Power light is ON.	System malfunction	Error code LEDs on main PC board.	Main PC Board.

Base function not operating properly

Symptom	Probable Cause	Check	Correction
No Base Up or Base Down	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	System malfunction	Error code LEDs on main PC board.	Main PC Board.
	Loose / damaged wire connections	Check wire connections to base actuator, base limit switches. Check black and white wire connections between main system transformer and main PC board.	Secure any loose connections.
	Base actuator / main PC board	Base Actuator / Limit Switches	Follow test sequence.
No Base Up. Base Down OK. OR No Base Down. Base Up OK.	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	System malfunction	Error code LEDs on main PC board.	Main PC Board.
	No Base Down Crash Avoidance System	Refer to: Crash Avoidance System	Determine appropriate test procedure(s) based on the theory of operation for the Crash Avoidance System.
	No Base Up Base Up limit switch. No Base Down Base Down limit switch.	Wire connections to limit switch.	If connections are OK, perform Limit Switch Test. Base Actuator / Limit Switch
	No Base Down Foot extension switch	Remove any obstructions under foot section of chair.	Perform Crash Limit Switch Test. Foot Extension / Crash Limit Switch.
	Base actuator / main PC board	Base Actuator / Limit Switches	Follow test sequence
Base drifts down.	Base actuator and gas springs	With no weight on chair, does base still drift down?	If YES, replace motor coupler and gas springs. If NO, replace base actuator. Base Actuator / Limit Switches
Noisy operation, grinding, squeaking, etc.	Gas springs / scissor mechanism	-	Clean / lubricate gas spring pivot joints. Wipe guide bars with a clean, dry cloth. Never lubricate guide bars or scissor mechanism! Gas Springs
Noisy operation, grinding, squeaking, etc.	Base actuator	Base Actuator / Limit Switches	Follow test sequence
Base function moves slowly, and/or will not lift patient.	Patient exceeded 450 lb weight limit	-	Inform staff that max patient weight is 450 lbs.
	Low voltage to chair	Check supply voltage. Required: 115 VAC ±10%	Connect adequate supply voltage.
	Base actuator motor	Perform Actuator Motor Test. Base Actuator / Limit Switches	Follow test sequence outlined.
	Gas springs	If actuator motor is OK	Replace gas springs. Gas Springs
Base function moves briefly, then stops and beeps.	Main PC board needs to be calibrated	Calibrate main PC board	Main PC Board.
	System malfunction	Error code LEDs on main PC board.	Main PC Board.
	Base position sensor	Wire connections to sensor. Perform Output Voltage Test at Sensor. Position Sensors	Follow test sequence.
	Base actuator / main PC board	Perform Actuator Motor Test. Base Actuator / Limit Switches	Follow test sequence.

Back function not operating properly

Symptom	Probable Cause	Check	Correction
No Back Up or Back Down	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	Loose / damaged wire connections	Check wire connections to back actuator and back limit switches. Check wire connections between main system transformer and main PC board, black and white wires.	Secure any loose connections.
	Back actuator / main PC board	Back Actuator / Limit Switches	Follow test sequence
No Back Up. Back Down OK. OR No Back Down. Back Up OK.	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	No Back Down -Crash Avoidance System	Crash Avoidance System	Determine appropriate test procedure(s) based on the theory of operation for the Crash Avoidance System.
	No Back Up - Back Up limit switch No Back Down- Back Down limit switch	Wire connections to limit switch.	Replace back limit switch / bracket assembly. Back Actuator / Limit Switches
	Back actuator / main PC board	Back Actuator / Limit Switches	Follow test sequence
Back drifts down.	Back actuator / motor coupler		Replace motor coupler. Back Actuator / Limit Switches
Noisy operation, grinding, squeaking, etc.	Back actuator	Back Actuator / Limit Switches	Follow instructions outlined
Back function moves slowly, and/or will not lift patient.	Patient exceeded 450 lb weight limit	-	Inform staff that max patient weight is 450 lbs.
	Low voltage to chair	Check supply voltage. Required: 115 VAC ±10%	Connect adequate supply voltage.
	Back actuator motor	Perform Actuator Motor Test. Back Actuator / Limit Switches	Follow test sequence outlined
Back function moves briefly, then stops and beeps.	Main PC board needs to be calibrated	Calibrate main PC board	Main PC Board
	Back position sensor	Wire connections to sensor. Perform Output Voltage Testing at the Sensors. Position Sensors	Follow test sequence outlined
	Back actuator / main PC board	Perform Actuator Motor Test. Back Actuator / Limit Switches	Follow test sequence outlined

Tilt function not operating properly

Symptom	Probable Cause	Check	Correction
No Tilt Up or Tilt Down	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	Loose / damaged wire connections	Check wire connections to tilt actuator, tilt down limit switch.	Secure any loose connections.
	Tilt actuator / main PC board	Tilt Actuator / Limit Switch	Follow test sequence
No Tilt Up. Tilt Down OK. OR No Tilt Down. Tilt Up OK.	Foot control / touch pad	Try activating functions from each touch pad / foot control.	Foot Control / Touch Pads
	No Tilt Up - Tilt position sensor	Refer to:Tilt Up Operation for description of proper operation.	Perform Output Voltage Testing at the Sensors. Position Sensors
	No Tilt Down - Tilt Down limit switch	Wire connections to limit switch.	If connections are OK, perform Limit Switch Test. Tilt Actuator / Limit Switch
	Tilt actuator / main PC board	Tilt Actuator / Limit Switch	Follow test sequence
Seat drifts down.	Tilt actuator / motor coupler		Replace motor coupler. Tilt Actuator / Limit Switch
Noisy operation, grinding, squeaking, etc.	Tilt actuator	Tilt Actuator / Limit Switch	Follow instructions outlined
Tilt function moves slowly, and/or will not lift patient.	Patient exceeded 450 lb weight limit		Inform staff that max patient weight is 450 lbs.
	Low voltage to chair	Check supply voltage. Required: 115 VAC ±10%	Connect adequate supply voltage.
	Tilt actuator motor	Perform Actuator Motor Test. Tilt Actuator / Limit Switch	Follow test sequence
Tilt function moves briefly, then stops and beeps.	Main PC board needs to be calibrated	Calibrate main PC board	Main PC Board
	Tilt position sensor	Wire connections to sensor. Perform Output Voltage Testing at the Sensors Position Sensors	Follow test sequence
	Tilt actuator / main PC board	Perform Actuator Motor Test. Tilt Actuator / Limit Switch	Follow test sequence

Multiple functions are inoperable, chair beeps

Symptom	Probable Cause	Check	Correction
Inoperable functions may include any of the following: Base Down, Back Down, Tilt Up, Tilt Down	Crash Avoidance System	Crash Avoidance System	Determine appropriate test procedure(s) based on the theory of operation for the Crash Avoidance System.

Programming feature does not work properly

Symptom	Probable Cause	Check	Correction
Positions cannot be programmed. Or When position button is pressed, chair does not move, or moves to wrong position.	Programming failed.		Reprogram desired position. Position Programming
Programming process error.	Error code LEDs on main PC board.	Main PC Board
Main PC board needs to be calibrated	Calibrate main PC board	Main PC Board

Symptom

Probable Cause

Check

Correction

Positions cannot be programmed.

When position button is pressed, chair does not move, or moves to wrong position.

Programming failed.

Reprogram desired position. Position Programming

Programming process error.

Error code LEDs on main PC board.

Main PC Board

Main PC board needs to be calibrated

Calibrate main PC board

Main PC Board

Problem Rotational base is malfunctioning

Symptom	Probable Cause	Check	Correction
Rotational brake will not lock.	Rotational brake mechanism	Unplug chair power cord. If base rotation locks, perform Rot. Brake Electrical Test. If base does not lock, inspect the mechanical brake components. Rotational Base Brake System.	Follow test sequence outlined.
Base wobbles when locked. and/or Grinding noise occurs as the base rotates.	Debris between upper and lower castings.		Without separating the castings, remove any debris.
	Loose hub screws	Four screws securing the upper and lower castings. For access instructions Refer to: Separating Upper and Lower Base Castings	Tighten screws.
	Rotation bearings / brake disc	Inspect needle bearing and brake disc for damage, debris, etc. Separating Upper and Lower Base Castings	Remove debris or replace base if necessary.
Rotational brake will not unlock.	Brake pedal switch	Check both brake pedals.	If either pedal works properly, check connections to faulty pedal switch. Replace switch if necessary. Rotational Base Brake System.
Rotational brake will not unlock.	Electro-magnet	Perform Electro-magnet Test. Rotational Base Brake System	Follow test sequence

No power at chair receptacles

Problem	Symptom	Probable Cause	Check	Correction
No power at chair receptacles.	There is power to the chair, but no power at the chair receptacles.	Loose / damaged wire connections	Wire connections between power inlet and chair receptacles	Correction Secure / repair wire connections.
Isolation transformer / receptacles	Perform Output Voltage Test. Chair Receptacles Isolation Transformer	Follow test sequence.

Problem

Symptom

Probable Cause

Check

Correction

No power at chair receptacles.

There is power to the chair, but no power at the chair receptacles.

Loose / damaged wire connections

Wire connections between power inlet and chair receptacles

Correction Secure / repair wire connections.

Isolation transformer / receptacles

Perform Output Voltage Test. Chair Receptacles Isolation Transformer

Follow test sequence.

Foot extension malfunctioning

Problem	Symptom	Probable Cause	Check	Correction
Foot extension malfunctioning.	Foot extension will not lock in place. Or Foot extension will not release.	Foot extension locking mechanism malfunctioning.	Perform Locking Mechanism Inspection. Foot Extension.	Follow instructions.

Problem

Symptom

Probable Cause

Check

Correction

Foot extension malfunctioning.

Foot extension will not lock in place.

Foot extension will not release.

Foot extension locking mechanism malfunctioning.

Perform Locking Mechanism Inspection. Foot Extension.

Follow instructions.

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647 Chair Troubleshooting Chart