Midmark 491-001,491-002 Service manual

491

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-001 thru -002

Power Otolaryngology Chair

Serial Number Prefixes: CT & DG

Service and

Parts Manual

FOR USE BY MIDMARK TRAINED TECHNICIANS ONLY

SF-1496 Part No. 004-0005-00 Rev. M (1/01/04)

491

-001 thru

-002

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TABLE OF CONTENTS

Section/Paragraph Page Section/Paragraph Page

IMPORTANT INSTRUCTIONS

General Safety Instructions......................................... ii

Safety Alert Symbols ................................................... ii

Warranty Instructions .................................................. ii

SECTION I GENERAL INFORMATION

1.1 Scope of Manual ......................................... 1-1

1.2 How to Use Manual ..................................... 1-1

1.3 Description of 491 Power Otolaryngology

Chair ......................................................... 1-1

1.4 Specifications ............................................. 1-4

1.5 Parts Replacement Ordering ....................... 1-4

1.6 Special Tools .............................................. 1-7

SECTION II TESTING AND TROUBLESHOOTING

2.1 Operational Test.......................................... 2-1

2.2 Troubleshooting Procedures ........................ 2-3

SECTION III SCHEDULED MAINTENANCE

3.1 Scheduled Maintenance .............................. 3-1

SECTION IV MAINTENANCE/SERVICE INSTRUCTIONS

4.1 Introduction ................................................. 4-1

4.2 Membrane Switch Panel Removal /

Installation ................................................ 4-1

4.3 Interface Board Removal / Installation.......... 4- 3

4.4 PC Control Board Removal / Installation ...... 4- 4

4.5 Back Actuator Removal / Installation ........... 4- 6

4.6 Back Capacitor Removal / Installation

(Domestic Units Only)............................... 4- 9

4.7 Thrust Bearing Removal / Installation......... 4-10

4.8 Base Actuator Removal / Installation ......... 4-13

4.9 Column Assembly Removal / Installation ... 4-17

4.1 0 Base Capacitor Removal / Installation

(Domestic Units Only)............................. 4-19

4.1 1 Typical Capacitor Removal / Installation

(Export Units Only) ................................. 4-20

4.1 2 Typical Actuator Motor / Actuator Brake

Removal / Installation ............................. 4-21

4.1 3 Base Down Limit Switch Removal /

Installation / Adjustment ......................... 4-22

4.1 4 Back Up Limit Switch Removal /

Installation / Adjustment ......................... 4-24

4.1 5 Typical Foot Pedal Footswitch Removal /

Installation .............................................. 4-25

4.1 6 Arm Rest Linkage Adjustment.................... 4-26

4.1 7 Chair Rotational Lock Adjustment .............. 4-27

4.1 8 Headrest Assembly Adjustment ................. 4-28

4.1 9 Headrest Handles Handle Stops

Adjustment ............................................. 4-29

4.2 0 Column Eccentric Tires Adjustment ........... 4-29

4.2 1 Foot Rest Stop Adjustment ........................ 4-31

4.22 Main Harness Replacement ....................... 4-32

SECTION V SCHEMATICS AND DIAGRAMS

5.1 Electrical Schematics / Wiring Diagrams...... 5- 1

5.2 Diagnostic L.E.D. Charts.............................. 5- 4

SECTION VI PARTS LIST

6.1 Introduction ................................................. 6-1

6.2 Description of Columns ............................... 6-1

6.3 Torque Specifications And Important

Assembly Notes ....................................... 6-1

Pictorial Index .............................................. 6-2

Upholstery Components ............................. 6-3.*

Chair Frame Assembly............................... 6-4.*

Headrest Assembly...................................... 6-5

Back Mechanism .......................................6-6.*

Linkage Mechanism ................................... 6-7.*

Back Actuator Assembly ...........................6-8.*

Seat Pivot Mechanism ...............................6-9.*

Elevation Column Assembly .................... 6-10.*

Base Assembly........................................ 6-11.*

Base Actuator Assembly ......................... 6-12.*

Receptacle Panel Assembly (Domestic) .. 6-13.*

Receptacle Panel Assembly (Export) ......... 6-14

COMMENTS ............................................................ 7-1

FAX ORDERING FORM .......................................... 7-2

(*) Indicates that there has been a serial number break for the illustration

and that there are additional point page(s) following the original page.

IMPORTANT INSTRUCTIONS

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General Safety Instructions

Safety First: The primary concern of Midmark Corporation is that this chair is maintained with the

safety of the patient and staff in mind. To assure that services and repairs are completed safely and correctly, proceed as follows:

(1) Read this entire manual before performing any

services or repairs on this chair.

(2) Be sure you understand the instructions

contained in this manual before attempting to service or repair this chair.

Safety Alert Symbols

Throughout this manual are safety alert symbols that call attention to particular procedures. These items are used as follows:

DANGER

A DANGER is used for an imminently

hazardous operating procedure, practice, or condition which, if not correctly followed, will result in loss of life or serious personal injury.

NOTE

A NOTE is used to amplify an operating procedure, practice or condition.

Warranty Instructions

Refer to the Midmark “Limited Warranty” printed in the Installation and Operation Manual for warranty information. Failure to follow the guidelines listed below will void the warranty and/or render the 491 Otolaryngology Chair unsafe for operation.

• In the event of a malfunction, do not attempt to operate the chair until necessary repairs have been made.

• Do not attempt to disassemble chair, replace malfunctioning or damaged components, or perform adjustments unless you are one of Midmark’s authorized service technicians.

• Do not substitute parts of another manufacturer when replacing inoperative or damaged components. Use only Midmark replacement parts.

WARNING

A WARNING is used for a potentially

hazardous operating procedure, practice, or condition which, if not correctly followed, could result in loss of life or serious personal injury.

CAUTION

A CAUTION is used for a potentially

hazardous operating procedure, practice, or condition which, if not correctly followed, could result in minor or moderate injury. It may also be used to alert against unsafe practices.

EQUIPMENT ALERT

An EQUIPMENT ALERT is used for an

imminently or potentially hazardous operating procedure, practice, or condition which, if not correctly followed, will or could result in serious, moderate, or minor damage to unit.

SECTION I

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GENERAL INFORMATION

SECTION I

GENERAL INFORMATION

1.1 Scope of Manual

This manual contains detailed troubleshooting, scheduled maintenance, maintenance, and service instructions for 491 Power Otolaryngology Chair. This manual is intended to be used by Midmark’s authorized service technicians.

1.2 How to Use Manual

A. Manual Use When Performing Scheduled Mainte-

nance. (1) Perform inspections and services listed in

Scheduled Maintenance Chart (Refer to para 3.1).

(2) If a component is discovered to be faulty or out

of adjustment, replace or adjust component in accordance with maintenance/service instructions (Refer to para 4.1).

B. Manual Use When Chair Is Malfunctioning And

Cause Is Unknown.

medical examinations and procedures on ears, noses, and throats.

The major serviceable components of the table are the PC control board, membrane switch panels, interface board, back actuator, back capacitor, base actuator, base capacitor, base down limit switch, back up limit switch, headlock assembly, elevation column assembly which includes eccentric bearings, chair rotational lock assembly, back linkage mechanism, pivot thust bearing, and foot control which includes four footswitches.

B. Theory of Operation (See Figures 5-1 and 5-2

for wiring diagrams / electrical schematics)

Electrical Power: Line voltage (115 VAC for domestic units and 230 VAC

for export units) is supplied to the chair's PC control board. There is a transformer and associated follow-on circuitry on the PC control board which reduces the line voltage to approximately 12 VDC. The 12 VDC provides power to operate the circuitry of the PC control board, membrane switch panels, and foot control.

(1) Perform an operational test on chair (Refer to

para 2.1).

(2) Perform troubleshooting procedures listed in

Troubleshooting Guide (Refer to para 2.2).

(3) If a component is discovered to be faulty or out

of adjustment, replace or adjust component in accordance with maintenance/service instructions (Refer to para 4.1).

C. Manual Use When Damaged Component Is Known.

(1) Replace or adjust component in accordance

with maintenance/service instructions (Refer to para 4.1).

1.3 Description Of 491 Power Otolaryngology Chair

A. General Description (See Figure 1-1).

The 491 Power Otolaryngology Chair is an examination chair designed specifically for performing general

On domestic units, 115 VAC is continuously supplied to the electrical receptacle. Export units do not have electrical receptacles.

Chair Operation using Switch Membranes or Hand Control:

When a manual function button is pressed, the switch membranes send signals to the PC control board using three data lines. The PC control board determines which function was selected by analyzing which data lines contained a signal and then the PC control board energizes the relay for the selected function.

There is always line voltage at the common contact (output) of the relays and there is a relay for each up and down function: BASE UP, BASE DOWN, BACK UP, and BACK DOWN. So, when a relay is energized, line voltage is applied thru the relay and then across the motor coil of the selected function, causing it to run. When the button is released, the function's relay is deenergized, removing line voltage from the motor coil which causes it to stop running. The BASE DOWN function has an additional control circuit to prevent it from being freewheeled at the end of its down travel.

SECTION I

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GENERAL INFORMATION

HEADLOCK

ASSEMBLY

MEMBRANE

SWITCH PANELS

EXPORT UNIT COMPONENTS

BACK

CAPACITOR

(EXPORT

UNITS ONLY)

BASE

CAPACITOR

(EXPORT

UNITS ONLY)

PIVOT

THRUST

BEARING

BACK UP

LIMIT SWITCH

INTERFACE

BOARD

ROTATIONAL

ASSEMBLY

FOOT

CONTROL

CHAIR

LOCK

BACK

LINKAGE

MECHANISM

PC CONTROL

BOARD

FOOT

SWITCHES

BASE

CAPACITOR

(DOMESTIC

UNITS ONLY)

BASE

ACTUAT OR

BACK

ACTUATOR

BACK

CAPACITOR

(DOMESTIC

UNITS ONLY)

ECCENTRIC

BEARINGS

BASE DOWN

LIMIT SWITCH

ELEVATION

COLUMN

ASSEMBL Y

MA312800

Figure 1-1. Major Components

SECTION I

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GENERAL INFORMATION

When the base down limit switch is tripped, the PC control board de-energizes the base down relay causing the base actuator to stop running (even if the button is still being depressed by the operator). This prevents the base actuator from being freewheeled when it reaches the end of its down travel. Otherwise, under heavy loads, excessive wear or damage to base actuator could result.

When the AUTO RETURN button is depressed, the switch membranes send signals to the PC control board using three data lines. The PC control board determines that the AUTO RETURN function was selected and energizes two relays: the BACK UP relay and the BASE DOWN relay. The PC control board keeps these functions running even when the operator releases the button. Then, the PC control board monitors the status of the normally open (N.O.) base down limit switch and N.O. back up limit switch. The N.O. limit switches are tripped, resulting in a closed circuit, when the actuators are in all positions but their auto return home position. When an actuator reaches its auto return home position, the limit switch becomes untripped and the PC control board de-energizes the relay for that function causing its actuator to stop. When both limit switches have become untripped, stopping both actuators, the auto return function is complete. The PC control board has a backup timing circuit in case the back up limit switch or base down limit switch malfunctions during the auto return function. If the PC control board does not see the status of both limit switches change within approximately 17 seconds of actuator run time, the backup circuit shuts down the auto return function.

The STOP button may be pressed at any time during the AUTO RETURN function. When the STOP button is pressed, the switch membranes send a signal to the PC control board. The PC control board determines that the STOP function was selected and stops the auto return function. This de-energizes the base down and back up relays, stopping the actuators.

Actuator Operation: The base and back actuators are ball screw driven.

The actuator assemblies contain a pivot point on the end of the ball screw. If an actuator assembly is run to the end of its stroke, the ball screw shaft spins inside the nut, which allows the actuator assembly to run without damaging or advancing the nut.

The base and back actuators have internal braking mechanisms which disengage when the motor starts running and engage when the motor stops running.

Diagnostic L.E.D. Information There are thirteen L.E.D.'s on the PC logic board which can be used for troubleshooting aids. Table 5-1 lists all functions for this chair and which L.E.D's should illuminate when a button or footswitch is depressed. See Figure 5-3 for location of L.E.D.'s.

• The back up relay L.E.D. illuminates to indicate that the PC control board is energizing the back up relay.

• The back down relay L.E.D. illuminates to indicate that the PC control board is energizing the back down relay.

• The base up relay L.E.D. illuminates to indicate that the PC control board is energizing the base up relay.

• The base down relay L.E.D. illuminates to indicate that the PC control board is energizing the base down relay.

• The foot control back up L.E.D. illuminates to indicate that the PC control board is receiving a good signal from the back up foot switch.

• The foot control back down L.E.D. illuminates to indicate that the PC control board is receiving a good signal from the back down foot switch.

• The foot control base up L.E.D. illuminates to indicate that the PC control board is receiving a good signal from the base up foot switch.

• The foot control base down L.E.D. illuminates to indicate that the PC control board is receiving a good signal from the base down foot switch.

• The auto return back function L.E.D. illuminates to indicate that the auto return circuit for the back function is activated. The L.E.D. stays illuminated until the back function has completed its portion of the auto return cycle.

• The auto return base function L.E.D. illuminates to indicate that the auto return circuit for the base function is activated. The L.E.D. stays illuminated until the base function has completed its portion of the auto return cycle.

• There are three Data Line L.E.D.'s; data line #1 L.E.D., data line #2 L.E.D., and data line #3 L.E.D.. Different combinations of these L.E.D's illuminate to indicate if the proper input signal is being sent to the PC control board from the membrane panels or hand control.

SECTION I

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GENERAL INFORMATION

General Information: All actuator motors have a thermal overload switch

which will activate if the actuator assembly is run continuously. The actuator motor was not designed for continuous operation. The normal cool off period for the thermal overload switches is 10 - 20 minutes.

Each actuator motor has a capacitor which provides start up power and motor run power.

There is a 0.25 amp fuse, located on the PC control board, which provides over-current protection to the control circuitry of the PC control board.

There are two 5 amp slow blow fuses, located on the PC control board, which provide over-current protection for each function's motor (i.e, Base fuse protects base actuator motor).

On older units, there is a switch on the PC control board labeled SW1; this switch must be in the OUT position or the back up limit switch will be bypassed. On newer units, there is a jumper connector; this jumper connector must be removed or the back up limit switch will be bypassed. This prevents the back function from moving when the auto return function is selected.

1.4 Specifications

Table Top Adjustment

Rotation................................................................330°

Back Section ...................................................2 to 90°

Table Top Height (Adjustable):.................... 22.0 in. to

31.0 in.

(55.9 cm to 78.7 cm)

Table Top Speeds (@ 60 Hz.):

Back Down ....................................... 11 +/- 1 seconds

Base Up ............................................ 12 +/-1 seconds

Weight Capacity (Maximum)............. 300 lb. (136.0 kg)

Electrical Requirements:

115 VAC Unit........................... 110 - 120 VAC, 60 HZ,

12 amp, single phase

230 VAC Unit...................... 220 - 240 VAC, 50/60 HZ,

10 amp, single phase

Power Consumption:

115 VAC Unit......................................... 1440 WATTS,

12 amps @ 120 VAC

230 VAC Unit........................................ 2400 WATTS,

10 amps @ 240 VAC

Recommended Circuit:

A separate (dedicated) circuit is recommended for

this chair. The chair

electrical circuit with other appliances or equipment

unless the circuit is rated for the additional load.

should not

be connected to an

Factual data for the 491 Power Otolaryngology Chair is provided in Table 1-1. Also, see Figure 1-2.

Table 1-1. Specifications

Description Data

Weight:

Without Shipping Carton................ 350 lb (158.8 kg)

With Shipping Carton..................... 375 lb (170.0 kg)

Shipping Carton....... 32 in. "L" x 29 in. "W" x 46 in. "H"

(81.2 cm x 73.66 cm x 116.8 cm)

Dimensions (See Figure 1-2):

Table Top Length (w/ headrest........ 75 in. (190.5 cm)

Table Top Width (w/o arm rests) .... 19.5 in. (49.5 cm)

Overall Width..................................... 26 in. (66.4 cm)

1.5 Parts Replacement Ordering

If a part replacement is required, order the part directly from the factory as follows:

(1) Refer to Figure 1-3 to determine the location of

the model number and serial number of the chair and record this data.

(2) Refer to the Parts List to determine the item

numbers of the parts, part numbers of the parts, descriptions of the parts, and quantities of parts needed and record this data (Refer to para 6.1).

NOTE

Ask the Purchasing Department of the company that

owns the chair for this information. Otherwise, this

information may be obtained from the dealer that

sold the chair.

75"

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TOTAL

LENGTH

SECTION I

GENERAL INFORMATION

24"

BASE

WIDTH

31"

MAXIMUM

HEIGHT

22"

MINIMUM

HEIGHT

26 1/2" WIDTH

ACROSS

ARMS

24 1/4"

SEAT

WIDTH

87°

0°

3°

POWER CORD

132"

24 1/4"

BASE

LENGTH

Figure 1-2. Chair Dimensions

FOOT CONTROL CORD

48"

MA312900

SECTION I

MIDMARK

MODEL NO.

INPUT

RATING

SERIAL NO.

491-00X

115 VAC

12 AMP 60 HZ

XX000000

MODEL

NUMBER

SERIAL

NUMBER

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GENERAL INFORMATION

Figure 1-3. Model Number / Serial Number Location

(3) Determine the installation date of the chair and

record this data.

(4) Call Midmark with the recorded information and

ask for the Medical Products Technical Services Department. See back cover of this manual for the phone number or use the Fax Order Form (See page 7-2 for Fax Order Form).

MIDMARK

491

DOWN

BACK

UP

DOWN

TABLE

UP

MA313000

1.6 Special Tools

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Table 1-2 lists all of the special tools needed to repair the chair, how to obtain the special tools, and the purpose of each special tool.

Table 1-2. Special Tool List

SECTION I

GENERAL INFORMATION

Description of Special Tool

Multimeter Commercially Available Any Type Used to perform continuity and volt age checks. Torque Wrench Commercially Available Any Type Used to t i ght en nuts or s cr ews to specified v alues.

Amp Extr act ion Tool Can be purchased from any

Manufacturer's

Name / Address / Phone

authorized Amp distributor.

Manufacturer's

Part Number

458994-2 Used to remove terminal sockets from amp

connectors.

Purpose of Special Tool

SECTION I

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GENERAL INFORMATION

TESTING AND TROUBLESHOOTING

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SECTION II

TESTING AND TROUBLESHOOTING

SECTION II

2.1 Operational Test

In order to effectively diagnose the malfunction of the chair, it may be necessary to perform an operational test as follows:

WARNING

Refer to the Operator Manual for

complete instructions on operating the chair. Failure to do so could result in personal injury.

NOTE

The Operational Test, for the most part, only describes what should happen when the chair is operated. If the chair does something other than described, a problem has been discovered. Refer to the Troubleshooting Guide to determine the cause of the problem and its correction.

(1) Plug the chair into a grounded, non-isolated,

correctly polarized outlet, that has the proper voltage output for the chair.

(4) Repeat steps 2 and 3 on the other membrane

switch panel. If the chair has a foot control, repeats steps 2 and 3 for these controls also.

(5) Raise BASE UP function all the way up and

BACK DOWN function all the way down.

(6) Press the AUTO RETURN button, wait one

second, and then press the STOP button.

(7) Observe. The BASE DOWN and BACK UP

functions should begin to run. When the STOP button is pressed, the base and back functions

should stop running. (8) Press the AUTO RETURN button again. (9) Observe. The base actuator should lower the

table top all the way down. The base actuator

should not continue to run after table top is

completely lowered. The back actuator should

raise the back section all the way up. The back

actuator should not continue to run after back

section is raised all the way up.

(2) Press BACK UP, BACK DOWN, BASE UP, and

BASE DOWN buttons on one of membrane switch panels.

(3) Observe. The table top should move in the

direction corresponding to the button which is being depressed. No section of the table top should drift on its own after membrane switch panel button is released. No actuator assembly should make excessive squealing noises. Movement should be steady and should match the speeds and positions listed below:

Chair Speeds (@ 60 Hz.):

Back Down (Up to Down) ................. 11 +/- 1 seconds

Base Up (Down To Up) ..................... 12 +/-1 seconds

Chair Positioning

Back Section ...................................................2 to 90°

Table Top Height (Adjustable): .....................22.0 in. to

31.0 in.

(55.9 cm to 78.7 cm)

(10) Unlock the pivot brake lever and rotate the

table top as far as it will go to the left and then

to the right.

(11) Observe. The table top should be able to be

rotated for approximately 330° of rotation.

Excessive force should not be required to

rotate table top and there should not be squeal-

ing or grinding noises coming from the pivot

point.

(12) Lock the brake lever. (13) Push on table at various points of the table top. (14) Observe. The column assembly should not

have excessive play.

(15) Unlock locking handle, position headrest in a

horizontal position as shown, and then relock

locking handle.

(16) Place a 45 lb (20.4 kg) static load at Point A.

SECTION II

BACK

SECTION

AXIS

"B"

AXIS

"C"

POINT

"A"

LOCKING

HANDLE

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TESTING AND TROUBLESHOOTING

MEMBRANE SWITCH PANEL

BACK UP

BUTTON

BACK

UP

BACK

DOWN

BASE

UP

BASE DOWN

AUTO

RETURN

STOP

BUTTON

BACK

DOWN

BUTTON

BASE UP

BUTTON

BASE

DOWN

BUTTON

AUTO RETURN BUTTON

TABLE

TOP

330°

ROTATION

TABLE

UP

TABLE

UP

FOOT CONTROL

FOOT SWITCHES

DOWN

BACK

UP

DOWN

TABLE DOWN

BRAKE

LEVER

MIDMARK

BACK

DOWN

BACK

UP

Figure 2-1. Operational Test

491

FOOT REST

MA312700

SECTION II

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TESTING AND TROUBLESHOOTING

(17) Observe. There should be no movement at

axis B or Axis C when the static load is applied to the headrest. The maximum force required to unclamp a locking handle should be 17 lbs. (7.7 kg) and the maximum force required to clamp a locking handle should be 35 lbs. (15.8 kg).

(18) Raise foot rest up to stowed position.

Table 2-1. Troubleshooting Guide

Problem Symptom Probable Cause Check Correction

Chair will not operate when any of the four up or down or auto return functions are selected from the membrane switch panels.

When any button is pressed, nothing happens (actuator motor(s) does not run or hum).

Nothing happens when a membrane button is pressed, but chair runs when a foot control foot switch is depressed.

(19) Observe. The foot rest should not fall down on

its own; it should stay locked in the stowed position.

2.2 Troubleshooting Procedures

Table 2-1 is a Troubleshooting Guide which is used to determine the cause of the malfunction.

Power cord is not plugged into facility wall outlet.

Facility circuit breaker providing power to chair is tripped.

Wire connections loose. Check all wiring

0.25 amp transformer primary fuse on PC control board is blown.

PC control board is malfunctioning.

Interface board is malfunctioning.

PC control board is malfunctioning.

Check to see if power cord is plugged in.

Check to see if facility circuit breaker is tripped. One way of checking this is to plug a lamp into wall outlet that chair was plugged into.

connections from power cord to PC control board. Perform continuity check on wires. Use multimeter to check for proper voltage levels.

Refer to Figure 5-1 or 5-2 for this check. Perform continuity check on primary fuse.

Replace suspect PC control board with known working PC control board or use diagnostic L.E.D. chart (Table 5-1) to determine location of malfunction.

Replace suspect interface board with known working interface board.

Replace suspect PC control board with known working PC control board or use diagnostic L.E.D. chart (Table 5-1) to determine location of malfunction.

Plug power cord into facility wall outlet.

If circuit breaker is tripped, determine what caused circuit breaker to trip, correct the problem, and then reset / replace circuit breaker.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace blown primary fuse.

Replace PC control board. Refer to para 4.4. If PC control board is not receiving proper inputs per Table 5-1, replace interface board Refer to para 4.3.

Replace interface board. Refer to para 4.3.

Replace PC control board. Refer to para 4.4. If PC control board is not receiving proper inputs per Table 5-1, replace interface board Refer to para 4.3.

SECTION II

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TESTING AND TROUBLESHOOTING

Table 2-1. Troubleshooting Guide - Continued

Problem Symptom Probable Cause Check Correction

One or more functions cannot be initiated from a membrane switch panel.

One or more functions cannot be initiated from the optional foot control.

BACK UP and BACK DOWN functions do not work. All other functions work.

Some functions may be initiated from a membrane switch panel, but at least one may not. All functions can be initiated from the other membrane switch panel.

Some functions may be initiated from the foot control, but at least one may not. All functions can be initiated from the membrane switch panel.

When BACK UP and BACK DOWN buttons are pressed, the chair will not move (all other functions work).

One of the button membranes on the membrane switch panel is malfunctioning.

Interface board is malfunctioning.

Foot switch for non-operable function is malfunctioning.

PC control board is malfunctioning.

Wire connections loose. Check all wiring

Back capacitor is weak or blown.

Thermal overload switch in back actuator is activated.

5 amp BACK fuse for BACK UP and BACK DOWN functions is blown (located on PC control board).

Back actuator assembly is malfunctioning.

Wire connections loose. Check all wiring

PC control board is malfunctioning.

Refer to Table 5-1 for this check. Press each button of membrane switch panel to verify that each button causes the appropriate L.E.D.’s on PC control board to illuminate.

Replace suspect interface board with known working interface board.

Perform a continuity check on suspect foot switch.

Refer to Table 5-1 and Figure 5-3 for this check. Depress each foot switch on foot control to verify that each footswitch causes the appropriate L.E.D.’s on PC control board to illuminate.

connections from foot control to PC control board. Perform continuity check on wires. Use multimeter to check for proper voltage levels.

Replace suspect back capacitor with known working back capacitor.

- Wait 10 to 20 minutes to allow

Refer to Figure 5-1 or 5-2 for this check. Perform a continuity check on 5 amp BACK fuse.

Replace suspect back actuator assembly with known working back actuator assembly.

connections to back actuator assembly.

Replace suspect PC control board with known working PC control board.

If appropriate L.E.D’s illuminate for each button, replace PC control board. Refer to para 4.4. If not, replace membrane switch panel. Refer to para 4.2.

Replace interface board. Refer to para 4.3.

Replace foot switch. Refer to para 4.15.

If appropriate L.E.D’s illuminate for each foot switch, replace PC control board. Refer to para 4.4. If not, replace malfunctioning foot switch. Refer to para 4.15.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace back capacitor. Refer to para 4.6 or 4.11.

back actuator motor to cool. Replace blown BACK fuse.

Replace actuator motor or back actuator assembly. Refer to para 4.12 or 4.5.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace PC control board. Refer to para 4.4.

Problem Symptom Probable Cause Check Correction

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BASE UP and BASE DOWN functions do not work. All other functions work.

BACK UP function works, but BACK DOWN function does not or BACK DOWN function works, but BACK UP function does not. All other functions work.

Table 2-1. Troubleshooting Guide - Continued

When BASE UP and BASE DOWN buttons are pressed, the chair will not move (all other functions work).

One function operates properly, but the other does not.

TESTING AND TROUBLESHOOTING

Base capacitor is weak or blown.

Thermal overload switch in base actuator is activated.

5 amp BASE fuse for BASE UP and BASE DOWN functions is blown (located on PC control board).

Base actuator assembly is malfunctioning.

Wire connections loose. Check all wiring

PC control board is malfunctioning.

Wire connections loose. Check all wiring

Back actuator assembly is malfunctioning.

PC control board is malfunctioning (relay for up or down function is malfunctioning).

Replace suspect base capacitor with known working base capacitor.

- Wait 10 to 20 minutes to allow

Refer to Figure 5-1 or 5-2 for this check. Perform a continuity check on 5 amp BASE fuse.

Replace suspect base actuator assembly with known working base actuator assembly.

connections to base actuator assembly.

Replace suspect PC control board with known working PC control board.

connections to back actuator assembly.

Replace suspect back actuator assembly with known working back actuator assembly.

Refer to Figure 5-3 for this check. Press BACK UP and then BACK DOWN button while observing the PC control board. The BACK UP RELAY L.E.D. should illuminate when the BACK UP button is pressed and the BACK DOWN RELAY L.E.D. should illuminate when the BACK DOWN button is pressed. If not, PC control board is malfunctioning.

SECTION II

Replace base capacitor. Refer to para 4.10 or 4.11.

tilt actuator motor to cool. Replace blown BASE fuse.

Replace actuator motor or base actuator assembly. Refer to para 4.12 or 4.8.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace PC control board. Refer to para 4.4.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace actuator motor or back actuator assembly. Refer to para 4.12 or 4.5

Replace PC control board. Refer to para 4.4.

SECTION II

Return To Table Of Contents

TESTING AND TROUBLESHOOTING

Table 2-1. Troubleshooting Guide - Continued

Problem Symptom Probable Cause Check Correction

BASE UP function works, but BASE DOWN function does not or BASE DOWN function works, but BASE UP function does not. All other functions work.

AUTO RETURN function does not work.

One function operates properly, but the other does not.

When AUTO RETURN button is pressed, nothing happens.

When AUTO RETURN button is pressed, BACK UP function does not run, but BASE DOWN function does.

Wire connections loose. Check all wiring connections to

Base actuator assembly is malfunctioning.

PC control board is malfunctioning (relay for up or down function is malfunctioning).

AUTO RETURN button on membrane switch panel is malfunctioning.

Interface board is malfunctioning.

The STOP button on membrane switch panel is malfunctioning (stuck closed).

Back up limit switch is malfunctioning (stuck open).

Older units - back bypass switch (SW1), located on PC control board, is pushed in. Newer units jumper connector is on both SW1 pins on PC control board.

PC control board is malfunctioning.

base actuator assembly.

Replace suspect base actuator assembly with known working base actuator assembly.

Refer to Figure 5-3 for this check. Press BASE UP and then BASE DOWN button while observing the PC control board. The BASE UP RELAY L.E.D. should illuminate when the BASE UP button is pressed and the BASE DOWN RELAY L.E.D. should illuminate when the BASE DOWN button is pressed. If not, PC control board is malfunctioning.

Refer to Table 5-1 and Figure 5-3 for this check. Press AUTO RETURN button of membrane switch panel and verify that the button causes the appropriate L.E.D.’s on PC control board to illuminate.

Replace suspect interface board with known working interface board.

Refer to Figure 5-3 for this check. If data line #1, #2, and #3 L.E.D.’s are all illuminated even though STOP button is not being pressed, membrane switch panel is malfunctioning.

Perform continuity check on back up limit switch. Limit switch tripped = continuity between COM. and N.O. terminals.

Refer to Figure 5-3 for this check. On older units, check to see if bypass switch (SW1) is pushed in. On newer units, check to see if jumper connector is on both SW1 pins.

Refer to Figure 5-3 for this check. After AUTO RETURN button is pressed, the auto return back function L.E.D. should illuminate and stay illuminated until the back section is all the way up.

Clean any dirty connections. Tighten any loose connections. Replace any damaged connections.

Replace actuator motor or base actuator assembly. Refer to para 4.12 or 4.8.

Replace PC control board. Refer to para 4.4.

If appropriate L.E.D’s illuminate for each button, replace PC control board. Refer to para 4.4. If not, replace membrane switch panel. Refer to para 4.2.

Replace interface board. Refer to para 4.3.

Replace membrane switch panel. Refer to para 4.2.

Replace back up limit switch. Refer to para 4.14.

On older units, pull bypass switch (SW1) to out position. On newer units, remove the jumper connector from SW1 pins and discard.

If not, replace PC control board. Refer to para 4.4. If L.E.D. does illuminate, replace interface board. Refer to para 4.3.

TESTING AND TROUBLESHOOTING

Return To Table Of Contents

Table 2-1. Troubleshooting Guide - Continued

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SECTION II

Return To Table Of Contents

TESTING AND TROUBLESHOOTING

Table 2-1. Troubleshooting Guide - Continued

Problem Symptom Probable Cause Check Correction

Chair moves fine for light patient, but will not move or moves slowly for very heavy patient.

Whirling or squeaking noise is heard when an actuator assembly is being run.

Excessive sideways play of table top.

Headrest is not operating properly.

Table top rotation is not working.

Foot rest will not lock into stowed position.

Heavy patients cause chair to malfunction.

Noisy actuator. Foreign matter on ball

Table top is not stable and can be moved from side to side.

Headrest drifts downward while supporting patients head.

Headrest locking handles pop out of locked position.

When table top is rotated, squealing noise is made and / or excessive force is required to rotate the table top.

The table top is rotating even though the pivot brake lever is in locked position.

When foot rest is raised into stowed position, it falls down by itself.

Low voltage is being supplied to chair.

Chair overloaded with too heavy of a patient.

Capacitor for suspect function is weak.

screw threads and / or lack of lubricant.

Eccentric tires are out of adjustment.

Headrest is out of adjustment.

Headrest handles handle stops need adjusted.

Thrust bearing is worn or damaged.

Chair rotational lock mechanism is out of adjustment.

Ball plungers are out of adjustment.

Check voltage at wall receptacle - should be 115 +/- 5 VAC for domestic units and 230 +/- 10 VAC for export units.

Maximum weight capacity of chair is 300 lbs (136.0 kg).

Replace suspect capacitor with known working capacitor.

Check for foreign matter on ball screw threads. Check for lack of lubricant on ball screw threads.

While observing the eccentric tires, run BASE UP function all the way up and then the BASE DOWN function all the way down. Any eccentric tires which do not come into contact with the inner column and rotate at least once during the full extension and retraction of the column assembly, need adjusted.

Check adjustment of headrest. Adjust headrest. Refer to

Check adjustment of headrest handles handle stops.

Replace suspect thrust bearing with known working thrust bearing.

Check adjustment of the chair rotational lock mechanism.

Check the adjustment of the ball plungers.

Correct low voltage situation at wall receptacle.

Inform chair operator of weight limitation.

Replace capacitor.

Clean all foreign matter off of ball screw threads. Coat ball screw threads with STP treatment oil or equivalent. If actuator assembly is still noisy, replace it.

Adjust eccentric tires. Refer to para 4.20.

para 4.18.

Adjust headrest handles handle stops. Refer to para

4.19. Replace thrust bearing.

Refer to para 4.7.

Adjust the chair rotational lock mechanism. Refer to para 4.17.

Adjust the ball plungers. Refer to para 4.21.

SCHEDULED MAINTENANCE

Return To Table Of Contents

SECTION III

SCHEDULED MAINTENANCE

SECTION III

3.1 Scheduled Maintenance

periodically on the chair. These inspections and services should be performed as often as indicated in

Table 3-1 is a Scheduled Maintenance Chart which lists

the chart.

the inspections and services that should be performed

Table 3-1. Scheduled Maintenance Chart

Interval Inspection or Service What to Do

Semi-annually Obvious damage Visually check condition of chair for obvious damage such as: cracks in components, missing

Fasteners / hardware Check chair for missing or loose fasteners / hardware. Replace any missing hardware and

Warning and instructional decals

Pivot points / moving parts / accessories

Membrane switch panel Check that all membrane switch buttons work when pressed. If not, replace membrane switch

Foot control (optional) Check that foot control works correctly. Make sure all footswitches operate properly. Replace

Auto return function Check that auto return function works correctly. Ensure each actuator stops running when it

Ball screws of actuator assemblies

Drifting of actuator assemblies

Arm rests The arm rest should be parallel to the seat section when the back section is all the way up. If not,

Chair rotational lock Move pivot brake lever to the "locked' position and then attempt to rotate the table top. If the

Table top rotation Check that table top can be rotated 330 degrees. Rotation should be easy and noiseless. If not,

Excessive play in column assembly

Headrest Check that headrest is adjusted properly and will not drift downward on its own under 45 lbs (20.4

Electrical receptacle (Domestic units only)

Upholstery Check all upholstery for rips, tears, or excessive wear. Replace cushions as necessary. Accessories Check that all accessories have all of their components and that they function properly. If

Operational Test Perform an Operational Test to determine if the chair is operating within its specifications (Refer

components, dents in components, or any other visible damage which would cause chair to be unsafe to operate or would compromise its performance. Repair chair as necessary.

tighten any loose hardware as necessary. Check for missing or illegible decals. Replace decals as necessary.

Lubricate all exposed pivot points, moving parts, and accessories with silicone based lubricant.

panel. Refer to para 4.2.

any malfunctioning footswitches. Refer to para 4.15.

reaches its end of travel and does not "freewheel". If necessary, adjust or replace limit switches. Refer to para 4.13 or 4.14.

Extend each actuator assembly and wipe ball screw threads down with a rag to remove foreign matter. Coat as much of the ball screw threads as possible with STP treatment oil or equivalent. Run each actuator assembly to both ends of its travel a couple of times to spread the oil evenly over all of the ball screw threads and then remove excess oil. If oil does not correct a squealing actuator assembly, replace actuator assembly.

Check each actuator assembly for drift. Replace actuator assembly brake components as necessary. Refer to para 4.12.

adjust the arm rest height. Refer to para 4.16.

table top rotates, adjust the rotational lock mechanism. Refer to para 4.17.

lubricate thrust bearing with vaseline or replace thrust bearing. Refer to para 4.7. Check that column assembly is stable and does not have excessive side to side play. Observe

the eccentric tires while running the BASE function all the way up and all the way down. Any eccentric tires which do not come into contact with the inner column and rotate at least once during the full extension and retraction of the column assembly, need adjusted. If necessary, adjust and / or replace eccentric tires. Refer to para 4.20.

kg) of static weight. If necessary, adjust headrest. Refer to para 4.18. Check that the electrical receptacle is functioning properly. Replace receptacle as necessary.

necessary, repair or replace the accessory.

to para 2.1). Replace or adjust any malfunctioning components.

SECTION III

Return To Table Of Contents

SCHEDULED MAINTENANCE

MAINTENANCE / SERVICE

Return To Table Of Contents

SECTION IV

MAINTENANCE / SERVICE INSTRUCTIONS

SECTION IV

4.1 Introduction

DANGER

Refer to the Operator Manual for

complete instructions on operating the chair. Failure to do so could result in personal injury.

NOTE

Perform an operational test on the chair after the repair is completed to confirm the repair was properly made and that

The following paragraphs contain removal, installation, repair, and adjustment procedures for the chair.

all

malfunctions were repaired.

4.2 Membrane Switch Panel Removal / Installation

A. Removal

NOTE

This art shows removal of the membrane switch panel from the patients right side of chair. Removal of membrane switch panel from patients left side of chair is the same.

(1) Raise BACK UP function all the way up. (2) Remove four screws (1, Figure 4-1) and

headrest assembly or headrest block (2) from back casting (3).

B. Installation

(1) Using warm soapy water, clean back casting

(3, Figure 4-2) in area where membrane switch panel (1) is to be installed. Allow to dry.

(2) Feed ribbon cable of membrane switch panel

(1) thru cable slot.

(3) Pull paper backing off of membrane switch

panel (1); then press membrane switch panel firmly into place on back casting (3).

EQUIPMENT ALERT

Use care not to bend, kink, or crease the

ribbon cable of the membrane switch panel. Failure to use care could result in damage to ribbon cable.

(4) Connect ribbon cable of membrane switch

panel (1) to interface board (2).

EQUIPMENT ALERT

Overtightening screws (7 and 8) could

cause back cover to crack.

NOTE

The shorter screws go on top.

(5) Install back cover (9, Figure 4-1) on back

casting (3) and secure with two long screws (8) and two short screws (7). Tighten screws until back cover starts to deform.

(3) If chair has an optional exam light assembly,

remove four screws (4) and exam light assembly (5) from light bracket (6).

(4) Remove two short screws (7), two long screws

(8), and back cover (9) from back casting (3).

(5) Disconnect ribbon cable of membrane switch

panel (1, Figure 4-2) from interface board (2).

(6) Using screwdriver, gently pry membrane switch

panel (1) off of back casting (3). Remove membrane switch panel (1) from back casting.

(6) If removed, install exam light assembly (5) on

light bracket (6) and secure with four screws (4).

(7) If removed, install headrest assembly or

headrest block (2) on back casting (3) and secure with four screws (1).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

5

3

9

2

4

6

1

7

Figure 4-1. Back Cover Removal / Installation

8

MA313100

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

RIBBON

3

CABLE

SLOT

CABLE

1

2

PAPER

BACKING

MA313200

Figure 4-2. Membrane Switch Panel

Removal / Installation

4.3 Interface Board Removal / Installation

(7) Remove four screws (4), spacers (5), interface

board (2), and light bracket (6) from back casting (7).

B. Installation

(1) Install light bracket (6), four spacers (5, Figure

4-4) and interface board (2) on back casting (7) and secure with four screws (4).

(2) Connect modular cord (3) to interface

board (2).

EQUIPMENT ALERT

Use care not to bend, kink, or crease the

ribbon cable of the membrane switch panel. Failure to use care could result in damage to ribbon cable.

(3) Connect two ribbon cables (1) to interface

board (2).

EQUIPMENT ALERT

Overtightening screws (7 and 8) could

cause back cover to crack.

A. Removal

(1) Raise BACK UP function all the way up. (2) Remove four screws (1, Figure 4-3) and

headrest assembly or headrest block (2) from back casting (3).

(3) If chair has an optional exam light assembly,

remove four screws (4) and exam light assembly (5) from light bracket (6).

(4) Remove two short screws (7), two long screws

(8), and back cover (9) from back casting (3).

(5) Disconnect two ribbon cables (1, Figure 4-4)

from interface board (2).

(6) Disconnect modular cord (3) from interface

board (2).

NOTE

Not all units have a light bracket (6).

NOTE

The shorter screws go on top.

(4) Install back cover (9, Figure 4-3) on back

casting (3) and secure with two long screws (8) and two short screws (7). Tighten screws until back cover starts to deform.

(5) If removed, install exam light assembly (5) on

light bracket (6) and secure with four screws (4).

(6) If removed, install headrest assembly or

headrest block (2) on back casting (3) and secure with four screws (1).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

5

3

9

2

4

6

1

7

Figure 4-3. Back Cover Removal / Installation

8

4.4 PC Control Board Removal / Installation

A. Removal

(1) If possible, raise BASE UP function all the way up.

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

MA313100

(2) Unplug chair power cord from wall outlet. (3) Remove four screws (1, Figure 4-5), four

screws (2), and R.H. and L.H. shrouds (3) from base mounts (4).

NOTE

Older units have a slightly different motor cover than is shown. Removal is similar.

(4) Remove two screws (5), four screws (6), and

motor cover (7) from elevation column (8).

(5) Disconnect three wire harnesses (1, Figure 4-

6) from PC control board (2).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(6) Tag and disconnect two modular cords (3) from

7

PC control board (2).

(7) Loosen five terminal screws (4); then tag and

disconnect five wires (5) from PC control board (2).

5

1

4

2

3

Figure 4-4. Interface Board Removal / Installation

6

MA313300

5

8

6

NOTE

There are two jumper strips which may fall off of terminal strip during disconnection of wires. Do not lose.

(8) Remove four screws (6), spacers (7), and PC

control board (2) from elevation column (8).

B. Installation

(1) Install PC control board (2, Figure 4-6) on

elevation column (8) and secure with four spacers (7) and screws (6).

7

3

MIDMARK

491

4

1

Figure 4-5. Shrouds and Motor Cover Removal / Installation

2

MA313400

SECTION IV

JUMPER

STRIP

3

4

5

1

2

6

7

9

9B

9A

8

Return To Table Of Contents

MAINTENANCE / SERVICE

(5) Connect three wire harnesses (1) to PC control

board (2).

EQUIPMENT ALERT

On older units, SW1 usually gets pushed

in when top wire harness is connected. SW1 must be in pulled out position for table to function properly.

(6) On older units, check position of SW1 (9). If

SW1 is not in pulled out position, pull SW1 out. On newer units, check to make sure jumper connector (9A) is not installed. If installed, remove jumper connector from SW1 pins (9B).

(7) Install motor cover (7, Figure 4-5) on elevation

column (8) and secure with four screws (6) and two screws (5).

(8) Install R.H. and L.H. shrouds (3) on base

mounts (4) and secure with four screws (2) and four screws (1).

Figure 4-6. PC Control Board Removal / Installation

(2) Make sure two jumper strips are installed on

terminal strip and did not fall out during wire disconnection.

(3) Connect five wires (5) to PC control board (2)

and secure by tightening five terminal screws (4).

(4) Connect two modular cords (3) to PC control

board (2).

(9) Plug chair power cord into wall outlet.

4.5 Back Actuator Removal / Installation

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) Unplug chair power cord from wall outlet.

MA313501

SECTION IV

2

EARLY

UNITS

9

8

10

11

7

LA TER

UNITS

16

15

14

19

20

17

21

2

12

13

18

Return To Table Of Contents

MAINTENANCE / SERVICE

(2) Remove upholstered seat section (1, Figure 4-

7) from seat casting (2) and upholstered back section (3) from upholstered back casting (4).

4

(3) Remove three screws (5) and seat cover (6)

from seat casting (2).

3

5

6

2

MIDMARK

491

1

MA313600

Figure 4-7. Wires Disconnection / Connection

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(4) On chairs with Serial Numbers CT-1000 thru

CT-1354 and DG-1000 thru DG-1099, perform the following steps:

a. Remove screw (7), ground wire (8), and

star washer (9) from seat casting (2).

b. Disconnect wire harness (10) from wire

harness (11).

(5) On chairs with Serial Numbers CT-1355 thru

Present and DG-1100 thru Present, perform the following steps:

a. Remove screw (12), ground wire (13), and

starwasher (14) from seat casting (2).

b. Disconnect wire harness (15) from wire

harness (16).

NOTE

If back actuator is being discarded, its three wires can be cut. If the back actuator is being removed for repair, an amp tool must be used or damage to socket terminals will result.

c. Using an amp tool, push three socket

terminals (17) from plug (15). See Table 1-2 for special tool.

15

7

14

15

16

18

12

17

11

8

1

9

17

10

4

d. Remove two screws (18) and strain relief

bracket (19) from seat casting (2).

e. Remove strain relief bushing (20) from

strain relief bracket (19).

f. Pull back actuator wires (21) from strain

relief bracket (19).

g. Remove strain relief bushing (20) from

back actuator wires (21).

(6) Cut cable tie (1, Figure 4-8) securing limit

switch wires (2) to shaft of back actuator (3).

(7) Remove two screws (4), lockwashers (5), and

separate limit switch bracket (6) from shaft of back actuator (3).

5

6

Figure 4-8. Back Actuator Removal / Installation

2

3

MA313700

CAUTION

Push arm rests out of the way or support

them while removing clevis pin. The arm rest will be free to fall, possibly resulting in minor injury to technician.

(8) Remove rue ring cotter pin (7) and clevis pin (8)

securing linkage assembly (9) to shaft of back actuator (3).

(9) Remove screw (10) and washer (11) securing

push rod assembly (12) to leg casting (13).

13

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(10) While supporting back casting (14), remove

two e-rings (15) and clevis pin (16) securing shaft of back actuator (3) and push rod assembly (12) to back casting (14).

(11) While supporting back casting (14), slide push

rod assembly (12) toward back of chair and then remove two screws (17) and back actuator (3) from seat casting (18).

B. Installation

EQUIPMENT ALERT

On newer units, do not attempt to install plug onto three socket terminals at this

time. Must be done later in procedure.

(1) Install back actuator (3, Figure 4-8) on seat

casting (18) and secure with two screws (17).

(2) Align shaft of back actuator (3) and push rod

assembly (12) with back casting (14) and secure with clevis pin (16) and two e-rings (15).

(3) Coat threads of screw (10) with removable

threadlocking adhesive (Loctite 242).

(4) Align push rod assembly (12) with leg casting

(13) and secure with washer (11) and screw (10).

(5) Connect linkage assembly (9) to shaft of back

actuator (3) with clevis pin (8) and rue ring cotter pin (7).

c. Connect wire harness (15) to wire har-

ness (16).

d. Connect ground wire (13) to seat casting

(2) and secure with starwasher (14) and screw (12).

e. Install strain relief bushing (20) on back

actuator wires (21) and then into strain relief bracket (19).

f. Install strain relief bracket (19) on seat

casting (2) and secure with two screws (18).

(9) On chairs with Serial Numbers CT-1000 thru

CT-1354 and DG-1000 thru DG-1099, perform the following steps:

a. Connect wire harness (10, Figure 4-7) to

wire harness (11).

b. Install starwasher (9) and ground wire (8)

on seat casting (2) and secure with screw (7).

(10) Install seat cover (6) on seat casting (2) and

secure with three screws (5).

(11) Install upholstered back section (3) on back

casting (4) and upholstered seat section (1) on seat casting (2).

(12) Plug chair power cord into wall outlet.

(6) Install limit switch bracket (6) on shaft of back

actuator (3) and secure with two lockwashers (5) and screws (4).

(7) Secure limit switch wires (2) to shaft of back

actuator (3) with a cable tie (1).

(8) On chairs with Serial Numbers CT-1355 thru

Present and DG-1100 thru Present, perform the following steps:

a. Feed back actuator wires (21, Figure 4-7)

thru strain relief bracket (19).

b. Insert three socket terminals (17) into

plug (15).

4.6 Back Capacitor Removal / Installation (Domestic Units Only)

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) Unplug chair power cord from wall outlet.

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(2) Remove upholstered seat section (1, Figure 4-

9) from seat casting (2).

(3) Remove three screws (3) and seat cover (4)

from seat casting (2).

(4) Remove two nuts (5) and capacitor cover (6)

from motor (7).

WARNING

A capacitor contains stored electricity.

Never touch terminals of a capacitor, even if power has been shut off or disconnected. Always discharge capacitor before touching capacitor terminals or wires. Failure to comply with these instruction could result in serious personal injury or death.

(5) Discharge capacitor (8). (6) Tag and disconnect two wires (9) from termi-

nals of capacitor (8). Remove capacitor.

B. Installation

(1) Connect two wires (9) to terminals of capaci-

tor (8). (2) Position capacitor (8) on motor (7). (3) Install capacitor cover (6) on motor (7) and

secure with two nuts (5). (4) Install seat cover (4) on seat casting (2) and

secure with three screws (3).

3

1

4

6

5

8

9

2

7

MA313800

Figure 4-9. Back Capacitor Removal / Installation

4.7 Thrust Bearing Removal / Installation

(5) Install upholstered seat section (1) on seat

casting (2). (6) Plug chair power cord into wall outlet.

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) Raise BACK UP function all the way up and

lower BASE DOWN function all the way down.

(2) Unplug chair power cord from wall outlet.

SECTION IV

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MAINTENANCE / SERVICE

(3) Remove four screws (1, Figure 4-10) and

headrest assembly or headrest block (2) from back casting (3).

(4) If chair has an optional exam light assembly,

remove four screws (4) and exam light assembly (5) from light bracket (6).

(5) Remove two short screws (7), two long screws

(8), and back cover (9) from back casting (3).

(6) Disconnect modular cord (10) from interface

board (11).

5

(7) On older units, cut cable tie (12) securing

modular cord (10) to back casting (3). On newer units, remove screw (13) securing cable tie (14) to back casting (3). Cut cable tie.

(8) Remove upholstered seat section (1, Figure 4-

11) from seat casting (2).

(9) Remove three screws (3) and seat cover (4)

from seat casting (2).

(10) Carefully pull modular cord (5) out of bush-

ing (6).

3

6

11

9

12

2

4

10

14

13

1

8

7

MA313900

Figure 4-10. Access To Back Section

SECTION IV

6

5

11

8

10

2

12

7

9

Return To Table Of Contents

MAINTENANCE / SERVICE

(14) Cut cable tie (1, Figure 4-12) securing two

wires (2) from shaft of back actuator (3).

(15) Tag and disconnect two wires (2) from back up

limit switch (4).

3

1

4

2

(16) Using a 1/8 inch Allen Wrench, loosen set-

screw (5).

(17) Unscrew seat nut (6) by turning in counter-

clockwise direction.

(18) Remove thrust washer (7), thrust bearing (8),

and thrust washer (9) from threaded post of slide weldment (10).

B. Installation

EQUIPMENT ALERT

Do not force seat nut if it does not thread

on fairly easily. The seat nut will just further damage the fine threads of the slide weldment and could require the slide weldment to be replaced.

(1) Inspect threads of slide weldment (10, Figure 4-

12). They are likely to be deformed because of the setscrew. If so, use a 20 threads per inch thread file to clean up the threads.

6

5

7

8

MA314000

Figure 4-11. Wires Disconnection / Connection

(11) Remove two screws (7) securing cable ties (8)

to seat casting (2).

(12) Remove screw (9) securing cable clamp (10) to

seat casting (2). Remove cable clamp from wires.

(13) Disconnect wire harness (11) from wire har-

ness (12).

Figure 4-12. Thrust Bearing Removal / Installation

10

1

9

2

4

3

MA314100

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(2) If re-installing old thrust washers (7 and 9) and

thrust bearing (8), clean with solvent. Allow to dry.

(3) Coat thrust washers (7 and 9) and thrust

bearing (8) with vaseline.

(4) Coat threads of slide weldment (10) and seat

nut (6) with vaseline.

(5) Install thrust washer (9), thrust bearing (8), and

thrust washer (7) on slide weldment (10).

NOTE

Seat nut should be installed on slide weldment so its counterbore is facing downward.

(6) Install seat nut (6) on slide weldment (10).

Tighten seat nut until no play can be felt when table top is rocked from side to side and table top has a small amount of resistance to being rotated.

(7) Secure seat nut (6) in position by tightening

setscrew (5) with 1/8 inch Allen Wrench.

(8) Connect one wire (2) to COM. terminal and the

other wire (2) to N.C. terminal of base up limit switch (4).

(15) Install seat cover (4) on seat casting (2) and

secure with three screws (3).

(16) Install upholstered seat section (1) on seat

casting (2).

(17) Connect modular cable (10, Figure 4-10) to

interface board (11).

(18) On older units, secure modular cord (10) to

back casting (3) with cable tie (12). On newer units, install cable tie (14) on modular cord (10); then secure cable tie (14) to back casting (3) with screw (13).

(19) Install back cover (9) on back casting (3) and

secure with two long screws (8) and two short screws (7). Tighten screws until back cover starts to deform.

(20) If removed, install exam light assembly (5) on

light bracket (6) and secure with four screws (4).

(21) If removed, install headrest assembly or

headrest block (2) on back casting (3) and secure with four screws (1).

(22) Plug chair power cord into wall outlet.

(9) Secure two wires (2) to shaft of back actuator

(3) with a cable tie (1).

(10) Connect wire harness (11, Figure 4-11) to wire

harness (12). (11) Install cable clamp (10) on wires. (12) Secure cable clamp (10) to seat casting (2) with

screw (9). (13) Secure two cable ties (8) to seat casting (2)

with two screws (7). (14) Feed modular cable (5) thru bushing (6).

4.8 Base Actuator Removal / Installation

A. Removal

(1) Remove thrust bearing (Refer to para 4.7). (2) Remove two outside bolts (1, Figure 4-13) and

lockwashers (2).

(3) Loosen two inside bolts (3) and remove brake

assembly (4) from seat casting (5).

(4) Remove stop (6) from seat casting (5).

SECTION IV

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MAINTENANCE / SERVICE

6

4

7

5

3

2

13

1

11

8

15

16

14

MIDMARK

491

11

10

9

12

Figure 4-13. Shrouds and Motor Cover Removal / Installation

WARNING

Table top is moderately heavy, but is

very bulky to lift. Use an assistant and use proper lifting techniques to lift the table top. Failure to do so could result in back injury.

MA314200

(5) With the help of an assistant, lift table top (7)

straight up off of slide weldment (8).

(6) Remove four screws (9), four screws (10), and

R.H. and L.H. shrouds (11) from base mounts (12).

NOTE

MA314301

2

4

5

13

14

JUMPER

STRIP

3

1

12

11

10

9

15

15B

15A

6

8

7

Return To Table Of Contents

Older units have a slightly different motor cover than is shown. Removal is similar.

(7) Remove two screws (13), four screws (14), and

motor cover (15) from elevation column (16).

(8) Disconnect three wire harnesses (1, Figure 4-

14) from PC control board (2).

(9) Tag and disconnect two modular cords (3) from

PC control board (2).

(10) Loosen five terminal screws (4); then tag and

disconnect five wires (5) from PC control board (2).

(11) Remove screw (6), ground wire (7), and star

washer (8) from elevation column (9).

SECTION IV

MAINTENANCE / SERVICE

(12) Remove screw (10) securing cable tie (11) to

base casting (12).

NOTE

There are two jumper strips which may fall off of terminal strip during disconnection of wires. Do not lose.

(13) Remove four screws (13), spacers (14), and

PC control board (2) from elevation column (9).

(14) Remove pin (1, Figure 4-15), spacer (2), and

rubber washer (3), securing shaft of base actuator (4) to slide weldment (5).

(15) Remove four screws (6) securing elevation

column (7) to base casting (8).

(16) Lift elevation column (7) off of base actuator (4)

and lay elevation column on base casting (8).

(17) Disconnect two capacitor wires (9) from two T-

taps (10).

(18) Tag and remove two T-taps (10) from base

actuator wires (11).

Figure 4-14. Wires Disconnection / Connection

(19) Using amp tool, tag and remove three base

actuator wires (11) from connector (12). If amp tool is not available, forcibly pull wires from connector (12). Refer to Table 1-2 for special tool.

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

4

3

5

7

(4) Install one T-tap (10) on red base actuator wire

(11) and one T-tap (10) on black base actuator wire (11).

(5) Connect two capacitor wires (9) to two

T-taps (10).

2

(6) Position elevation column (7) over base actua-

tor (4) and lower onto base casting (8).

1

(7) Secure elevation column (7) on base casting

(8) with four screws (6).

6

11

4

8

10

15

12

9

14

13

MA314400

Figure 4-15. Base Actuator Removal / Installation

EQUIPMENT ALERT

Facing table from rear, spacer (2) goes

on the left and rubber washer (3) goes on the right. Failure to install correctly, could result in premature wear of base actuator and / or excessive noise.

(8) Align shaft of base actuator (4) with slide

weldment (5); then secure shaft of base actuator to slide weldment (5) with rubber washer (3), spacer (2), and pin (1).

(9) Secure cable tie (11, Figure 4-14) to base

casting (12) and secure with screw (10).

(10) Install starwasher (8) and ground wire (7) on

elevation column (9) and secure with screw (6).

(11) Make sure two jumper strips are installed on

terminal strip of PC control board (2).

(12) Connect five wires (5) to PC control board (2)

and secure by tightening five terminal screws (4).

(20) Remove hitch pin clip (13), clevis pin (14), and

base actuator (4) from actuator mount (15).

B. Installation

(1) Install base actuator (4, Figure 4-15) on actua-

tor mount (15) and secure with clevis pin (14) and hitch pin clip (13).

(2) Rotate shaft of new base actuator (4) until it is

extended to approximately same length as old base actuator.

(3) Insert three base actuator wires (11) into

connector (12).

(13) Connect two modular cords (3) to PC control

board (2).

(14) Connect three wire harnesses (1) to PC control

board (2).

EQUIPMENT ALERT

On older units, SW1 usually gets pushed

in when top wire harness is connected. SW1 must be in pulled out position for table to function properly.

(6) On older units, check position of SW1 (15). If

SW1 is not in pulled out position, pull SW1 out. On newer units, check to make sure jumper

SECTION IV

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MAINTENANCE / SERVICE

connector (15A) remove jumper connector from SW1 pins (15B).

(16) Install motor cover (15, Figure 4-13) on eleva-

tion column (16) and secure with four screws (14) and two screws (13).

(17) Install R.H. and L.H. shrouds (11) on base

mounts (12) and secure with four screws (10) and four screws (9).

(18) Coat top surface of slide weldment (8) with

vaseline.

is not

installed. If installed,

WARNING

Table top is moderately heavy, but is

very bulky to lift. Use an assistant and use proper lifting techniques to lift the table top. Failure to do so could result in back injury.

(19) With the help of an assistant, lift table top (7)

and position it on slide weldment (8), making sure to route all wires thru center hole of table top.

(3) Remove four nuts (1, Figure 4-16), screws (2),

and two base mount angles (3) from elevation column (4).

(4) Remove four screws (5), spacers (6), and PC

control board (7) from elevation column (4).

(5) Remove screw (8), ground wire (9), and

starwasher (10) from elevation column (4).

NOTE

This step applies only to newer units. Older units do not have a switch cover.

(6) Remove two screws (11) and switch cover (12)

from elevation column (4).

(7) Remove two nuts (1, Figure 4-17), lockwashers

(2), screws (3), and base down limit switch (4) from elevation column (5).

(20) Install stop (6) in seat casting (5), making sure

that bevel of stop is in horizontal position.

NOTE

Do not tighten bolts tightly. The brake assembly will need to be adjusted later.

(21) Install brake assembly (4) on seat casting (5)

and secure by tightening two inside bolts (3) and installing two outside lockwashers (2) and

bolts (1). (22) Install thrust bearing (Refer to para 4.7). (23) Adjust the chair rotational lock (Refer to

para 4.17). (24) Plug chair power cord into wall outlet.

4.9 Column Assembly Removal / Installation

A. Removal

10

4

9

8

12

6

5

1

7

3

Figure 4-16. Removal / Installation of External

Components of Column Assembly

2

MA314500

11

(1) Remove thrust bearing (Refer to para 4.7). (2) Remove base actuator (Refer to para 4.8).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(10) Remove screw (10) securing cable clamp (11)

to slide weldment (12).

B. Installation

(1) Install cable clamp (11, Figure 4-17) on slide

weldment (12) and secure with screw (10).

12

11

10

(2) Install cable clamp (9) on elevation column (5)

and secure with screw (8).

(3) Secure cable tie (7) on elevation column (5)

and secure with screw (6).

(4) Install base down limit switch (4) on elevation

column (5) and secure with two screws (3), lockwashers (2), and nuts (1).

NOTE

This step applies only to newer units. Older units do not have a switch cover.

9

5

(5) Install switch cover (12, Figure 4-16) on eleva-

tion column (4) and secure with two screws (11).

3

8

(6) Install starwasher (10) and ground wire (9) on

elevation column (4) and secure with screw (8).

(7) Install four spacers (6) and PC control board (7)

on elevation column (4) and secure with four screws (5).

1

7

6

Figure 4-17. Removal / Installation of Internal

Components of Column Assembly

(8) Remove screw (6) securing cable tie (7) to

elevation column (5).

(9) Remove screw (8) securing cable clamp (9) to

elevation column (5).

2

4

MA314600

(8) Install two base mount angles (3) on elevation

column (4) and secure with four screws (2) and nuts (1).

(9) Install base actuator (Refer to para 4.8). (10) Install thrust bearing (Refer to para 4.7). (11) Plug chair power cord into wall outlet.

4.10 Base Capacitor Removal / Installa-

9

12

11

10

TAB

CATCH

Return To Table Of Contents

tion (Domestic Units Only)

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

SECTION IV

MAINTENANCE / SERVICE

3

(1) If possible, raise BASE UP function all the way

up. (2) Unplug chair power cord from wall outlet. (3) Remove four screws (1, Figure 4-18), four

screws (2), and R.H. and L.H. shrouds (3) from

base mounts (4).

NOTE

Older units have a slightly different motor cover than is shown. Removal is similar.

(4) Remove two screws (5), four screws (6), and

motor cover (7) from elevation column (8). (5) Using a screwdriver, pry tab of mounting

bracket (9) outward and separate base capaci-

tor (10) from mounting bracket. (6) Remove capacitor cap (11) from base capaci-

tor (10).

WARNING

The capacitor contains stored electric-

tor, even if power has been disconnected. Always discharge capacitor before touching capacitor terminals or wires. Failure to comply with these instructions could result in serious personal injury or death.

(7) Discharge base capacitor (10).

ity. Never touch terminals of capaci-

7

5

6

MIDMARK

491

3

Figure 4-18. Base Capacitor Removal / Installation

B. Installation

(1) Connect one wire (12) to each terminal group of

base capacitor (10).

(2) Install capacitor cap (11) on base capaci-

tor (10).

1

4

2

MA314700

8

(8) Disconnect two wires (12) from terminals of

base capacitor (10) and remove base capaci-

tor.

SECTION IV

12

10

9

11

16

17

18

14

15

Return To Table Of Contents

MAINTENANCE / SERVICE

(3) Position the bottom of base capacitor (10) on

mounting bracket (9) and then push the top of

the capacitor inward. Using a screwdriver,

force the tab of the mounting bracket (9) down

over the catch of the capacitor cap (11). Make

sure base capacitor (10) is held firmly in place. (4) Install motor cover (7) on elevation column (8)

and secure with four screws (6) and two

screws (5). (5) Install R.H. and L.H. shrouds (3) on base

mounts (4) and secure with four screws (2) and

four screws (1). (6) Plug chair power cord into wall outlet.

4.11 Typical Capacitor Removal / Installation (Export Units Only)

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) If possible, raise BASE UP function all the way

up. (2) Unplug chair power cord from wall outlet. (3) Remove four screws (1, Figure 4-19), four

screws (2), and R.H. and L.H. shrouds (3) from

base mounts (4).

NOTE

Older units have a slightly different motor cover than is shown. Removal is similar.

(4) Remove two screws (5), four screws (6), and

motor cover (7) from elevation column (8).

7

5

6

MIDMARK

491

3

Figure 4-19. Typical Capacitor

Removal / Installation (Export Units Only)

1

4

2

3

8

13

MA314800

WARNING

Return To Table Of Contents

The capacitor contains stored electric-

ity. Never touch terminals of capacitor, even if power has been disconnected. Always discharge capacitor before touching capacitor terminals or wires. Failure to comply with these instructions could result in serious personal injury or death.

SECTION IV

MAINTENANCE / SERVICE

a. Install base capacitor (9) on base casting

(13) and secure with capacitor clamp (12) and two screws (11).

b. Connect two wires (10) to terminals of

back capacitor (9).

(3) Connect one wire (10) to each terminal group of

capacitor (9).

(5) To remove the base capacitor, perform the

following steps: a. Discharge base capacitor (9). b. Disconnect two wires (10) from terminals

of base capacitor (9).

c. Remove two screws (11), capacitor clamp

(12), and base capacitor (9) from base casting (13).

(6) To remove the back capacitor, perform the

following steps: a. Discharge back capacitor (14). b. Disconnect two wires (15) from terminals

of back capacitor (14).

c. Remove two screws (16), capacitor clamp

(17), and back capacitor (14) from bracket (18).

B. Installation

(4) Install motor cover (7) on elevation column (8)

and secure with four screws (6) and two screws (5).

(5) Install R.H. and L.H. shrouds (3) on base

mounts (4) and secure with four screws (2) and four screws (1).

(6) Plug chair power cord into wall outlet.

4.12 Actuator Motor / Actuator Brake Removal / Installation

(Applies To Both Actuator Assemblies with Serial Numbers CT1000 thru CT3191 and DG1000 thru DG1432)

A. Removal

(1) Remove malfunctioning actuator assembly:

Back actuator assembly (Refer to para 4.5). Base actuator assembly (Refer to para 4.8).

(2) Remove two nuts (1, Figure 4-20) and actuator

motor (2) from actuator mechanism (3).

(1) To install the back capacitor, perform the

following steps; then continue with step 3: a. Install back capacitor (14) on bracket (18)

and secure with capacitor clamp (17) and two screws (16).

b. Connect two wires (15) to terminals of

back capacitor (14).

(2) To install the base capacitor, perform the

following steps; then continue with step 3:

(3) Remove two shoulder washers (4) from actua-

tor mechanism (3).

(4) Remove spacer (5) and motor coupler (6) from

shaft of actuator motor (2).

NOTE

A needle nose pliers should be used to extract the actuator brake from the actuator mechanism. Grasp the raised round plate of the actuator brake with the pliers and pull.

(5) Remove actuator brake (7) and rubber damper

(8) from shaft of actuator mechanism (3).

SECTION IV

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MAINTENANCE / SERVICE

1

4

KEYS

6

(5) Install actuator assembly:

Back actuator assembly (Refer to para 4.5). Base actuator assembly (Refer to para 4.8).

(6) Check actuator assembly for proper operation.

The actuator assembly should run normally and should not make a grinding noise; this indicates that key slots of motor coupler were not aligned properly with keys of actuator mechanism (the grinding noise also indicates that the motor coupler is being damaged). The actuator assembly should brake properly.

3

KEY

SLOTS

2

8

KEY

7

SLOT

Figure 4-20. Actuator Motor / Actuator Brake

B. Installation

5

MA314900

Removal / Installation

NOTE

The rubber damper must be installed so its flat side faces the inside of the actuator mechanism. The actuator brake must be installed so its flattest side faces outward. The shaft of the actuator mechanism may be turned with a screwdriver to help align the keys of the actuator mechanism shaft with the key slots in actuator brake.

(1) Install rubber damper (8), actuator brake (7),

and spacer (5) in actuator mechanism (3).

(2) Install motor coupler (6) on shaft of actuator

motor (2).

(3) Install two shoulder washers (4) in actuator

mechanism (3).

(4) Align keys of actuator mechanism (3) shaft with

key slots of motor coupler (6) and then install actuator motor (2) on actuator mechanism (3) and secure with two nuts (1).

4.13 Base Down Limit Switch Removal / Installation / Adjustment

A. Removal

(1) If possible, raise BASE UP function all the way

up.

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(2) Unplug chair power cord from wall outlet. (3) Remove four screws (1, Figure 4-21), four

screws (2), and R.H. and L.H. shrouds (3) from base mounts (4).

NOTE

Older units have a slightly different motor cover than is shown. Removal is similar.

(4) Remove two screws (5), four screws (6), and

motor cover (7) from elevation column (8).

NOTE

This step applies only to newer units. Older units do not have a switch cover.

(5) Remove two screws (1, Figure 4-22) and

switch cover (2) from elevation column (3).

SECTION IV

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MAINTENANCE / SERVICE

3

7

5

6

MIDMARK

491

3

Figure 4-21. Shrouds and Cover

Removal / Installation

(6) Insert index finger thru access hole to hold nuts

(4); then remove two nuts (4). lockwashers (5), screws (6), and base down limit switch (7) from elevation column (3).

(7) Pull base down limit switch (7) thru access

hole.

(8) Disconnect wire harness (8) from base down

limit switch (7).

B. Installation

(1) Connect wire harness (8) to base down limit

switch (7).

(2) Push base down limit switch (7) thru access

hole.

1

4

2

8

MA315000

3

6

8

ACCESS

HOLE

4

5

7

Figure 4-22. Base Down Limit Switch

Removal / Installation / Adjustment

(3) Using index finger, position base down limit

switch (7) on elevation column (3) and secure with two screws (6), lockwashers (5), and nuts (4).

C. Adjustment

NOTE

If performing adjustment procedure only, perform steps 1 thru 5 of removal to gain access to base down limit switch.

(1) Raise BASE UP function approximately 6 in.

(15.2 cm). (2) Press the AUTO RETURN button and observe. (3) If base actuator continues to run after table top

is completely lowered, loosen two nuts (4) and

raise base down limit switch (7) slightly.

Tighten two nuts (4).

2

1

MA315100

(4) Repeat steps 1 thru 3 until base actuator

automatically stops running after table top is

completely lowered.

SECTION IV

10

9

5

12

11

6

8

Return To Table Of Contents

MAINTENANCE / SERVICE

NOTE

This step applies only to newer units. Older units do not have a switch cover.

(5) Install switch cover (2) on elevation column (3)

and secure with two screws (1).

(6) Install motor cover (7, Figure 4-21) on elevation

column (8) and secure with four screws (6) and two screws (5).

(7) Install R.H. and L.H. shrouds (3) on base

mounts (4) and secure with four screws (2) and four screws (1).

(8) Plug chair power cord into wall outlet.

4.14 Back Up Limit Switch Removal / Installation / Adjustment

4

3

1

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) Unplug chair power cord from wall outlet. (2) Remove upholstered seat section (1, Figure 4-

23) from seat casting (2).

(3) Remove three screws (3) and seat cover (4)

from seat casting (2).

(4) Cut cable tie (5) securing two wires (6) from

shaft of back actuator (7).

(5) Remove two nuts (8), lockwashers (9), screws

(6) Tag and disconnect two wires (6) from back up

(10), and back up limit switch (11) from switch bracket (12).

limit switch (11).

7

2

MA315200

Figure 4-23. Back Up Limit Switch

Removal / Installation / Adjustment

B. Installation

(1) Connect one wire (6) to COM. terminal and

other wire (6) to N.C. terminal of back up limit switch (11).

(2) Install back up limit switch (11) on switch

bracket (12) and secure with two screws (10), lockwashers (9), and nuts (8).

SECTION IV

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MAINTENANCE / SERVICE

C. Adjustment

NOTE

If performing adjustment procedure only, perform steps 1 thru 3 of removal to gain access to back up limit switch.

(1) Lower BACK DOWN function approximately 6

in. (15.2 cm).

(2) Press the AUTO RETURN button and observe.

NOTE

Determining a comfortable "chair" position is based upon opinion. If necessary, find out from the person using the table what "chair" position is best for his / her needs.

(3) If back section stops in a comfortable "chair"

position, adjustment is not necessary. If back section stops in too low a position, loosen two nuts (8), slide back up limit switch (11) away from actuator motor and then retighten nuts. If back section stops in too high a position, loosen two nuts (8), slide back up limit switch (11) toward actuator motor and then retighten nuts.

4.15 Typical Foot Pedal Footswitch Removal / Installation

A. Removal

(1) Remove screw (1, Figure 4-24), lockwasher

(2), and footswitch pedal (3) from switch mount (4).

PIVOT

BALL

2

3

7

9

6

5

8

1

(4) Repeat steps 1 thru 3 until back section stops

in a comfortable "chair" position.

(5) Secure two wires (6) to shaft of back actuator

(7) with cable tie (5).

(6) Install seat cover (4) on seat casting (2) and

secure with three screws (3).

(7) Install upholstered seat section (1) on seat

casting (2).

(8) Plug chair power cord into wall outlet.

10

4

PIVOT

TAB

BRACKET

Figure 4-24. Typical Foot Pedal Footswitch

Removal / Installation

MA315300

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(2) Remove nut (5), screw (6), footswitch (7), and

two insulators (8) from bracket of switch mount (4).

(3) Tag and disconnect two wires (9) from termi-

nals of footswitch (7).

B. Installation

(1) Connect one wire (9) to COM. terminal and

other wire (9) to N.O. terminal of footswitch (7).

(2) Install two insulators (8) and footswitch (7) on

bracket of switch mount (4) and secure with screw (6) and nut (5).

5

(3) Ensure springs (10) are in position on posts

and have not fallen off.

(4) Install footswitch pedal (3) on switch mount (4)

and secure with lockwasher (2) and screw (1), making sure pivot ball of footswitch pedal is mounted in pivot tab of switch mount.

4.16 Arm Rest Linkage Adjustment

A. Adjustment

(1) Remove four screws (1, Figure 4-25) and

headrest assembly or headrest block (2) from back casting (3).

3

6

13

9

12

10

11

2

1

4

PARALLEL

8

7

MA315400

Figure 4-25. Arm Rest Linkage Adjustment

(2) If chair has an optional exam light assembly,

Return To Table Of Contents

remove four screws (4) and exam light assembly (5) from light bracket (6).

(3) Remove two short screws (7), two long screws

(8), and back cover (9) from back casting (3). (4) Lower BACK DOWN function all the way down. (5) Press AUTO RETURN button. (6) Loosen jam nut (10). (7) Adjust linkage rod (11) until arm castings (12)

are parallel with seat casting (13). (8) While holding linkage rod stationary, tighten

jam nut (10). (9) Install back cover (9) on back casting (3) and

secure with two long screws (8) and two short

screws (7). Tighten screws until back cover

starts to deform.

(10) If removed, install exam light assembly (5) on

light bracket (6) and secure with four

screws (4).

(11) If removed, install headrest assembly or

headrest block (2) on back casting (3) and

secure with four screws (1).

SECTION IV

MAINTENANCE / SERVICE

1

2

3

Figure 4-26. Chair Rotational Lock Adjustment

(5) If the braking action is too light, repeat steps 1

thru 4 again, pushing stop weldment (3) in even further toward column. If the braking action is too hard, repeat steps 1 thru 4 again, but move stop weldment (3) away from column slightly.

(6) Repeat steps 1 thru 5 until braking action of

chair rotational lock is satisfactory.

COLUMN

MA315500

4.17 Chair Rotational Lock Adjustment

A. Brake Adjustment

(1) Rotate brake lever (1, Figure 4-26) to the

"unlocked" position. (2) Loosen four bolts (2). (3) Push stop weldment (3) in toward column and

then tighten four bolts (2). (4) Rotate brake lever (1) to the locked position

and attempt to rotate the table top.

B. Brake Lever Adjustment

(1) Loosen two setscrews (1, Figure 4-27). (2) Rotate brake lever (2) until it is in vertical

position.

(3) Rotate cam stop (3) until raised portion of cam

is pointing toward floor.

(4) Retighten two setscrews (1).

SECTION IV

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MAINTENANCE / SERVICE

TEST SETUP

BACK

SECTION

POINT

"A"

HEADREST

ASEMBL Y

2

3

2

VERTICAL

1

RAISED

PORTION

TO

FLOOR

MA315600

Figure 4-27. Brake Lever Adjustment

4.18 Headrest Assembly Adjustment

A. Adjustment

NOTE

The standard headrest assembly is shown in this illustration. The procedure for adjusting all headrests which can be used on this chair is the same.

(1) Unlock locking handle (See Figure 4-28).

AXIS

1

LOCKING

HANDLE

Figure 4-28. Headrest Assembly Adjustment

(2) Loosen setscrew (1, Figure 4-28). (3) Tighten adjusting screw (2) slightly; then lock

locking handle. Repeat this step until Axis A and B have the strongest possible holding power, but operation of locking handle is not

too difficult. (4) Tighten setscrew (1). (5) Lower BACK DOWN function all the way down. (6) Position headrest assembly as shown in TEST

SETUP.

"A"

AXIS

"B"

MA315700

NOTE

LOCKING

HANDLE

1

2

Return To Table Of Contents

The maximum force required to unclamp a locking handle should be 17 lbs (7.7 kg) and the maximum force required to clamp a locking handle should be 35 lbs (15.8 kg).

(7) Place a 45 lb (20.4 kg) weight on headrest

assembly at Point A.

DANGER

Failure to adjust headrest assembly to

specifications could result in a failure during a procedure. This could cause severe personal injury to a patient or the need to terminate the procedure.

SECTION IV

MAINTENANCE / SERVICE

(8) Observe. The headrest assembly should

support the test weight without drifting downward. If not, repeat entire adjustment procedure. If headrest assembly does not meet test standards, do not use headrest assembly.

4.19 Headrest Handles Handle Stops Adjustment

A. Adjustment

NOTE

The standard headrest assembly is shown in this illustration. The procedure for adjusting all headrests which can be used on this chair is the same.

(1) Loosen nut (1, Figure 4-29). (2) Push on locking handle until it reaches a point

where the locking handle wants to lock itself by going over center; then allow locking handle to go over center a few degrees. Hold the locking handle in this position and adjust stop screw (2) so the locking handle will be forced to stop in this position each time it is locked.

(3) Tighten nut (1).

MA315800

Figure 4-29. Headrest Locking Handle

Stop Adjustment

4.20 Column Eccentric Tires Adjustment

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before removing any of the chair's covers/shrouds or making any repairs to prevent the possibility of electrical shock. Failure to comply with these instructions could result in severe personal injury or death.

(1) If possible, raise BASE UP function all the way

up. (2) Unplug chair power cord from wall outlet. (3) Remove four screws (1, Figure 4-30), four

screws (2), and R.H. and L.H. shrouds (3) from

base mounts (4).

NOTE

Older units have a slightly different motor cover than is shown. Removal is similar.

(4) Remove two screws (5), four screws (6), and

motor cover (7) from elevation column (8).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

NOTE

All concentric tire bearings are designated with the letter A. All eccentric tire bearings are designated with the letter B.

(5) Check tightness of concentric bolts (1, Figure

4-31). Tighten all concentric bolts (1) to 15 ftlbs (20.3 N•m).

(6) Lower BASE DOWN function all the way down;

then raise BASE UP function all the way up while observing one of the eccentric bearings (B).

(7) Observe. Any eccentric bearing, which does

not make contact and rotate at at least one point during the raising of the column, needs to be adjusted.

(8) Loosen bolt (2) for eccentric bearing (B)

needing adjusted.

NOTE

Rotate thick portion of center post as close to the fin of the inner slide weldment (3) as possible, so tire bearing will place the maximum pressure on the fin of the inner slide weldment, resulting in a stable column. The reason for turning the center post in a clockwise direction is because there is a tendency for the thick portion of center post to rotate even further toward the fin of the inner slide weldment when its bolt is tightened. If the center post was rotated in the other direction, tightening the bolt would have the tendency to rotate the thick portion of center post away from the fin of inner slide weldment.

(9) Rotate center post of tire, as far as possible in

clockwise direction, until thick portion of center

post is facing toward fin of inner slide weld-

ment (3).

(10) Tighten bolt (2) to 15 ft-lbs (20.3 N•m).

5

7

8

3

6

MIDMARK

491

3

4

1

2

MA315900

Figure 4-30. Shrouds and Motor Cover Removal / Installation

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

CONCENTRIC TIRE

BEARING ASSEMBL Y

CONCENTRIC

SPINDLE

A

ECCENTRIC TIRE

BEARING ASSEMBL Y

CENTER

POST

ECCENTRIC

SPINDLE

B

OUTER

TIRE

THICK

PORTION

FINS

(13) Install R.H. and L.H. shrouds (3) on base

mounts (4) and secure with four screws (2) and four screws (1).

(14) Plug chair power cord into wall outlet.

4.21 Foot Rest Stop Adjustment

A. Adjustment

NOTE

Perform this adjustment if foot rest will not stay in the stowed position by itself.

(1 ) Raise foot rest (1, Figure 4-32) up to the

stowed position.

A

B

2

MA316000

Figure 4-31. Column Eccentric Tires Adjustment

(11) Repeat steps 6 thru 10 until all eccentric

bearings (B) have been observed and adjusted as necessary.

(12) Install motor cover (7, figure 4-30) on elevation

column (8) and secure with four screws (6) and two screws (5).

B

1

4

3

HOLE

3

1

2

HOLE

Figure 4-32. Footrest Stop Adjustment

(2 ) Loosen two setscrews (2).

MA316100

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

(3 ) While holding foot rest (1) in stowed position,

align hole in pin weldment (3) with ball plunger (4).

(4 ) Push in on pin weldment (3) while tightening

setscrew (2). Repeat for other setscrew.

1

2

4.22 Main Harness Replacement

A. Removal

WARNING

Always disconnect the power cord

from the wall outlet before working on chair. Failure to comply with these instructions could result in personal injury.

(1 ) Remove thrust bearing (Refer to para 4.7). (2 ) Remove brake assembly (1, Fig. 4-33) (four

bolts) and the stop (2).

3

5

4

MA31420

4

Figure 4-33. Main Harness

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

WARNING

Use two people to lift table from col umn. Failure to do so could result in

personal injury.

(3) Using an assistance, lift table top (3) off

column. (4 ) Remove shrouds (4). (5 ) Disconnect wire harness (1, Fig. 4-34) from PC

board (2). (6 ) Remove ground wire (3).

2

3

1

4

5

1

2

MA31430

Figure 4-34. Main Harness

(7 ) Remove pin (1, Fig.4-35), spacer (2), and rubber

washer (3). (8 ) Remove mounting bolts (4) and lift column

assembly (5) from actuator shaft.

MA628401i

Figure 4-35. Main Harness

NOTE

Lay column on its side, as shown in Figure 36, and remove existing wiring harness.

B. Installation

NOTE

Wire harness must be routed as shown (Figure 36). Loose wire leads at bottom of column must be twisted and secured to prevent damage during movement of slide.

(1 ) Route wire harness thru column.

End (1, Fig. 4-36) of harness with

longest protruding cordset (phone connector) goes thru top of column.

(2 ) Secure harness to slide weldment (2) with cable

clamp (3). Locate clamp 1/4" from end of flex guard.

(3 ) Carefully twist loose leads together (4) and

secure to column with cable tie (5).

SECTION IV

Return To Table Of Contents

MAINTENANCE / SERVICE

4

1

5

3

2

Figure 4-36. Main Harness

(4 ) Install column assembly (5, Fig. 4-35) and

secure with mounting bolts (4). (5 ) Install pin (1), spacer (2), and rubber washer (3). (6 ) Install ground wire (2, Fig. 4-34) and connect

wire harnesses (1) to PC board. (7 ) Coat top surface of slide weldment (5, Fig. 4-33)

with vaseline.

MA628501i

(8 ) While feeding wire harness thru center hole of

table top (3), position top on slide weldment (5).

(9 ) Install brake assembly (1) but do not tighten

mounting bolts or adjust brake until after the thrust bearing has been installed.

(1 0) Install thrust bearing (Refer to para 4.7).

SCHEMATICS AND DIAGRAMS

Return To Table Of Contents

SECTION V

SCHEMATICS AND DIAGRAMS

SECTION V

5.1 Electrical Schematics / Wiring Diagrams

Figures 5-1 and 5-2 illustrate the logic/current flow and

See next page for Figure 5-1

wiring connections between the electrical components in the chair.

SECTION V

Return To Table Of Contents

SCHEMATICS AND DIAGRAMS

Backup

Back Dwn

Base Up

Base Down

Auto Return

Stop

015-0013-00

M

Base

Actuator

(029-1406-00)

120 Volt AC

12 Amperes 60Hz

(Incl. Accessory

Receptacle)

Foot Control

Switches

(002-0101-00)

Membrane Switch Panel 015-0721-00

Connector J1

(015-0391-00)

12

T-Tap

3

4

56

White

(015-0685-00)

Black

Red

Power Cord (015-0066-09)

Up

Down

Up

Down

Foot Switch (Optional)

015-0257-00

Red

Black

White

Table

Back

(015-0534-00)

015-0701-00

Capacitor

36-43 M.F .D.

(015-0437-02)

(015-0702-00)

Black Red White

Green Blue Orange

Red Black White

(015-0590-02)

W/Sleeving

(015-0794-00)

Wiring Harness

Green

White

Diode P.C. Board 015-0712-01

J7

Blue Orange

Connector

J6

Red

1

Black

2

White

3

Plug

Connector

[Male]

[Female] (015-0591-02)

NOTE: On older style PC Control boards, make sure "S1" is in the pushed in position. On newer style PC boards, make sure the jumper connector is installed on both S1 pins.

Connector J5

(015-0590-01)

1

2

Blue

Orange

White

Black

(015-0700-00)

BRLS2

(N.O.)

Base Down Limit Switch

Black

(015-0635-00)

123 4

56

789

White

101112

Green

Connector J2

(015-0443-00)

Foot Switch Harness

(015-0699-00)

2

6

4

3

1

5

BRLS1

(N.O.)

Green / Yellow

(015-0147-01)

Jumper

Orange

Blue Red Black

3

6

2

Back Up Limit Switch (015-0430 -00)

Green

J2

J5

1 2 3 4 5 6 7

K3

015-0022-00

K4

Black (015-0680-00) White (015-0680-01)

5

4

1

5

4

3

Backup

Back Dwn

Base Up

Base Down

Auto Return

Stop

(029-1230-00)

J4

J3 J3

PC Control

S1

Board

(015-0696-00)

TB1

T1

F1

F3

F2

J1

Black White

Green

J8

Casing

J8

6

5

4

3

Receptacle

Panel

Assembly

6

1

7

2

Casing

M

Back

Actuator

K1

K2

Red

7

1

2

Membrane Switch Panel 015-0721-00

Capacitor

36-43 M.F .D.

(015-0437-02)

(015-0346-04)

.25 Amp-250 Volts

(015-0346-03)

5 Amp-250 Volts

015-0540-00

015-0524-00

6.0 Amps Max. (015-0083-01)

(015-0101-01)

Green / Y ellow

MA212504

015-0535-07

Black

Red

Yellow

Coupler

Receptacle

Green

Figure 5-1. Domestic Electrical Schematic / Wiring Diagram

SECTION V

Return To Table Of Contents

SCHEMATICS AND DIAGRAMS

Backup

Back Dwn

Base Up

Base Down

Auto Return

Stop

015-0013-00

White

M

Base

Actuator

(029-1406-01)

220/240 Volt AC

10 Amperes 50/60Hz

Foot Control

Switches

(002-0101-00)

Membrane Switch Panel 015-0721-00

Capacitor

17.5 M.F .D. 370 V.A.C.

(015-0438-03)

T-Tap

(015-0685-00)

White

(015-0685-00)

T-Tap

White

Connector J1

(015-0391-00)

3

56

Black

Red

Power Cord (015-0066-09)

Green

Down

Foot Switch (Optional)

015-0257-00

Red

Black

12 4

White

Up

Table

Up

Back

(015-0534-00)

White

015-0701-00

Capacitor

17.5 M.F .D. 370 V.A.C.

(015-0438-03)

(015-0702-00)

Black

Red

White

Green Blue

Orange

Red Black White

(015-0590-02)

W/Sleeving

(015-0722-00)

Wiring Harness

White

Diode P.C. Board 015-0712-01

J7

Blue Orange

Connector

J6

Red

1

Black

2

White

3

Plug

Connector

[Male]

[Female] (015-0591-02)

NOTE: On older style PC Control boards, make sure switch "S1" is in the pulled out position. On newer style PC boards, make sure the jumper connector is not installed on both S1 pins; remove and discard jumper connector.

Connector J5

(015-0590-01)

1

2

Blue Orange White Black

(015-0700-00)

BRLS2

(N.O.)

Base Down Limit Switch

Black

(015-0635-00)

123 4

56

789

White

101112

Green

Connector J2

(015-0443-00)

Foot Switch Harness

(015-0699-00)

6

4

1

2

5

Green / Yellow (015-0147-01)

Orange

Blue Red Black

2

3

BRLS1

(N.O.)

Jumper

015-0022-00

1

3

6

Back Up Limit Switch (015-0430-00)

Green

J2

S1

J5

1 2 3 4

TB1

5

F1

6 7

F3

K3

K4

5

4

6

5

4

2

3

Backup

Back Dwn

Base Up

Membrane Switch Panel

Base Down

015-0721-00

Auto Return

Stop

M

Back

Actuator

(029-1230-01)

J4

J4 J3 J3

PC Control

Board

(015-0696-01)

T1

F2

K1

J1

K2

Black White

Red

Green

J8

Casing

J8

7

6

3

Receptacle

Panel

Assembly

7

1

2

5

4

1

Casing

(015-0346-04)

.25 Amp-250 Volts

015-0535-07

(015-0346-03)

5 Amp-250 Volts

Black

Yellow

Coupler

015-0540-00

015-0524-00

MA212602

Red

Green

Figure 5-2. Export Electrical Schematic / Wiring Diagram

SECTION V

Return To Table Of Contents

SCHEMATICS AND DIAGRAMS

5.2 Diagnostic L.E.D. Charts

Table 5-1 can be used to troubleshoot the chair thru diagnosis of a function's L.E.D. status. The first column

Table 5-1. Diagnostic L.E.D. Chart

Selected Function Button L.E.D's Which Should Be Illuminated When Function Is Selected

lists each function that may be selected by an operator. The second column lists which L.E.D's will illuminate, when a particular function is selected when the unit is functioning properly. See Figure 5-3 for L.E.D. locations.

Hand Control

BASE UP button data line #1 L.E.D. / data line #3 L.E.D. / base up relay L.E.D. BASE DOWN button data line #2 L.E.D. / data line #3 L.E.D. / base down relay L.E.D. BACK UP button data line #1 L.E.D. / back up relay L.E.D. BACK DOWN button data line #2 L.E.D. / back down relay L.E.D. AUTO RETURN button data line #3 L.E.D. / auto return back function L.E.D. /

auto return base function L.E.D. / base down relay L.E.D. / back up relay L.E.D.

STOP button data line #1 L.E.D. / data line #2 L.E.D. / data line #3 L.E.D.

Foot Control

BASE UP foot pedal foot control base up L.E.D. / base up relay L.E.D. BASE DOWN foot pedal foot control base down L.E.D. / base down relay L.E.D. BACK UP foot pedal foot control back up L.E.D. / back up relay L.E.D. BACK DOWN foot pedal foot control back down L.E.D. / back down relay L.E.D.

NOTE: All amber L.E.D's stay illuminated only as long as their function button is depressed. The two green auto

return function L.E.D's remain illuminated until their actuators have reached their limits and their limit switches have become untripped.

Description of each L.E.D's meaning when illuminated