A-dec Dental Chair Service manual
85.0812.00, 2003 CH-1
Chairs Overview
A-dec model 1040, 1021 and 8000 chairs are electronically controlled, hydraulically powered
dental chairs. Buttons on both the touchpad and 8-button footswitch and actuators on the
8-function footswitch are used to position and program auto-positioning functions into the chair.
The hydraulic system is controlled by the electronic control module using relays and solenoidactuated valves.
This section provides information related to locating serial/model numbers, servicing,
maintenance, and adjustment of chairs. Detail on how to service chairs and troubleshoot specific
problems related to them is presented.
Locating
Serial/Model
Number
85.0812.00, 2003 CH-2
Chairs Serial/Model Number Locations
Cascade 1040 ChairDecade 1021/1011 Chair
Serial number
label location
Serial number
label location
The serial/model number tags identify the chair model and manufacture date. The label can be
found either on the top surface of a chair’s upper structure (raise the toeboard) or on the righthand side of the upper structure. If you have difficulty locating the serial/model number label,
the following example may be helpful.
85.0812.00, 2003 CH-3
Chairs Manufacture Date
Serial/Model Number Label
Reading the
Manufacture Date
1
Item # Description
1Model number
2 The first letter of the serial number
indicates the month the product was
manufactured; e.g., A is January.
3First digit indicates the year
of manufacture.
2
1
Different models of the chair can be identified by referring to the “REF” number. Each chair is further
identified by its month and year of manufacture.
This example shows how to identify the model and month and year of manufacture of the chair.
2601 CRESTVIEW DRIVE
®
NEWBERG, OREGON 97132 USA
Designated EU Representative: A-dec Dental U.K., Ltd.
Austin House, 11 Liberty Way, Attleborough Fields,
Nuneaton, Warwickshire, England CV 116RZ
DENTAL
CHAIR
Tele: (44) 1203-350901
REF: 1040
S/N: J167856
2001
MADE IN
USA
!
DENTAL CHAIR
INPUTS
-
120 V
10 AMPS MAX
50-60 Hz
CAUTION!
U
®
LISTE
15VJ
S
D
C
LABEL P/N: 051.515.02 REV L
85.0812.00, 2003 CH-4
Chairs Hydraulics
Working with
Hydraulics
Part Description
Hydraulic fluid reservoir The fluid level in the reservoir can be seen through the sides of the reservoir and is serviced via a
top fill cap.
Hydraulic cylinders The hydraulic cylinders control the base lift and back functions. Springs and gravity retract the
rod during base and back down functions.
Motor-driven hydraulic pump The hydraulic pump and the starter capacitor supply hydraulic fluid from the reservoir, under
pressure, to the chair lift and tilt hydraulic cylinders for back up and base up functions.
Solenoid/manifold assembly This assembly gates hydraulic fluid to and from the two cylinders. Depending on the chair
function called for, the controller selects which solenoid-actuated manifold valves are opened or
closed. The solenoid/manifold assembly also includes four adjustable needle valves used to
restrict or divert the flow of hydraulic fluid to and from the lift and tilt cylinders. These valves
provide the rate of travel adjustment for chair base and back movement.
The hydraulic system consists of the following:
85.0812.00, 2003 CH-5
Chairs Hydraulic System Flow Diagram
From
motor/pump
start capacitor
{
Solenoid
manifold
assembly
Tilt cylinder
Lift cylinder
Vent tubes
Pickup tube
Hydraulic fluid reservoir (check fluid level with base and
back full up)
NOTE: Use only A-dec fluid P/N 61.0197.00.
Hydraulic
pump
motor
MAX
MIN
85.0812.00, 2003 CH-6
Chairs Hydraulic Manifold
Hydraulic Manifold
Item # Part Number Description
1 61.1335.00 Solenoid, (8-watt, 100V,
Yellow wires)
61.1336.00 Solenoid, (8-watt, 120 V,
Black wires)
61.1337.00 Solenoid, (8-watt, 240 V,
Red wires)
2 035.041.02 O-ring, special pkg 10
3 030.004.02 O-ring, AS568-004 pkg 10
4 030.010.00 O-ring, AS568-010
(only on dual-block manifolds)
5 61.0460.00 Flow adjust screw with o-ring
6 001.002.00 Screw, truss-head slot
1
2
3
4
5
6
3
3
Before January 1999
85.0812.00, 2003 CH-7
Chairs Hydraulic Manifold
Hydraulic Manifold
Item # Part Number Description
1 61.1335.01 Solenoid, (8-watt, 100V,
Yellow wires)
61.1336.01 Solenoid, (8-watt, 120V,
Black wires)
61.1337.01 Solenoid, (8-watt, 240V,
Red wires)
2 030.015.02 O-ring, pkg 10
3 030.004.02 O-ring, AS568-004 pkg 10
4 61.0460.00 Flow adjust screw with o-ring
5 002.118.01 Screw, button-head, socket
6 61.1332.00 Manifold assy, hyd, 100V
61.1333.00 Manifold assy, hyd, 120V
61.1334.00 Manifold assy, hyd, 240V
3
4
5
2
6
1
3
After January 1999
85.0812.00, 2003 CH-8
Chair Hydraulic Manifold
The following steps will guide you through the
removal of a solenoid.
Task Description
1 Lower the chair base and back to the
full down position to depressurize the
hydraulic system. Remove the motor
pump cover, then unplug the chair.
2 If necessary, remove the two mounting
screws that secure the manifold to the
hydraulic tray. Rotate the manifold so
the solenoids are accessible.
3Using a flat blade screwdriver and a 9/16"
wrench, remove the defective solenoid.
4 Cut the defective solenoid wires 3" (74mm)
from the coil and discard.
5Remove the old o-ring from the solenoid
cavity and completely dry the cavity.
Replace the o-ring (refer to Solenoid
installation instructions for correct o-ring).
Hydraulic manifold
O-ring
Poppet sleeve
Washer
ID washer
Retaining nut
Poppet
Coil
Wire nut
J10
Removing a
Solenoid
WARNING
The solenoid coils are
powered by line voltage
(100, 120, or 240V AC).
Failure to unplug the
chair may result in
serious injury from
electrical shock.
Removing a Solenoid
85.0812.00, 2003 CH-9
Chair Hydraulic Manifold
The following steps will guide you through
replacing a solenoid.
Task Description
1 Install the new solenoid stem and poppet into
the manifold and tighten to 35-40 in lb
(.11085-.2284 Nm). Position the remaining
solenoid parts on the stem and secure by
tightening the retaining nut to 25-30 in lb
(.14275-.1713 Nm).
2 Cut the solenoid wires 3" (75 mm) from the coil.
Install the stripped wires from the solenoid and
the connector housing into a wire nut. Repeat
for the remaining wire.
3Using the mounting screws, secure the
manifold to the hydraulic tray.
4. Plug in the chair. Test the chair functions to
ensure proper operations and that no fluid
leakage occurs. Reinstall the motor pump cover.
Hydraulic manifold
O-ring
Poppet sleeve
Washer
ID washer
Retaining nut
Poppet
Coil
Wire nut
J10
Replacing a
Solenoid
WARNING
The solenoid coils are
powered by line voltage
(100, 120, or 240V AC).
Failure to unplug the
chair may result in
serious injury from
electrical shock.
Replacing a Solenoid
85.0812.00, 2003 CH-10
Chairs Hydraulic Manifold
Base down
control valve
Base up
control valve
Back down
control valve
Back up
control valve
CAUTION
Do not completely close
a speed control valve.
The motor/pump could
overheat and become
damaged from pumping
against a closed valve.
Do not remove retaining
screw from the control
valves.
Retaining
screw
The hydraulic manifold incorporates four speed control valves, which restrict or divert the flow of
hydraulic fluid to and from the lift and tilt cylinders.
NOTE: The speed control valves are hex drive.
To adjust... Do this...
Base up speed Turn base up control valve:
clockwise to decrease speed, or
counterclockwise to increase speed.
Base down speed Turn base down control valve:
clockwise to decrease speed, or
counterclockwise to increase speed
Back up speed Turn back up control valve
counterclockwise to decrease speed, or
clockwise to increase speed.
NOTE: This is opposite of the other
three control valves. Turning the back
up valve counterclockwise too far may
prevent the back from moving up.
Back down speed Turn the back down control valve:
clockwise to decrease speed, or
counterclockwise to increase speed.
Adjusting the Hydraulic Manifold
Adjusting the
Hydraulic Manifold
85.0812.00, 2003 CH-11
Chairs Hydraulic Manifold
Task Description
1 Remove the motor/pump cover from the chair.
2 Fit a 5/8" wrench to the high pressure outlet port
(either lift or tilt, whichever is in hydrostatic lock) of
the hydraulic manifold. Hold the port still and use a
9/16" wrench to loosen the hose fitting.
3 Place a shop rag around the fitting to absorb
the fluid.
4 Carefully loosen the fitting counterclockwise until oil
begins to leak from the fitting. Retighten the fitting.
Operate the down function. A second release of
hydraulic fluid may be required.
5 Adjust the limit switch that caused the hydrostatic
lock (refer to Adjusting the Base Up Limit Switch). In
some cases, it may be necessary to remove and
replace the limit switch. Adjust the new limit switch
as needed. Also ensure that the large gear/actuator
is securely installed and not slipping.
6Cycle the chair a couple of times to verify it is no
longer in hydrostatic lock.
Tilt cylinder
high pressure
fitting
Lift cylinder
high pressure
fitting
Correcting
Hydrostatic
Lock
Hydraulic lock occurs based on the following conditions:
•chair base or back is stuck in full up position
• limit switch not activated, or
• down solenoid poppet is unable to open based on excess hydraulic pressure.
Correcting Hydrostatic Lock
85.0812.00, 2003 CH-12
Chairs Electrical System Wiring Diagram
Optional duplex
100V and 120V only
Ground
Footswitch
LED light
Back positioning
potentiometer
Base positioning
potentiometer
Main power from
electrical outlet
Hydraulic manifold
To post box, or
Radius lift arm connector
Stop plate
limit switches
Base up limit
switch
Back up limit
switch
Capacitor
To hydraulic
motor/pump
}
To cuspidor
stop switch
NOTE: If there is no cuspidor, remove
jumper from cable and place
on board
Place jumper
here if there is
no cuspidor
DS8
P
17
BKUP
BSU
P
BSDN
BK
DN
PRGM
0
PRGM
1
PRGM
2
PRGM
3
EN/DIS TP/F
FACT DEFAU
BK POT
BS PO
T
SPAR
E
SPAR
E
"STATIC SENSITIVE
CUSP/RET
AST POS
T
L
PRGM
3
NOT USE
D
+12V +5V
P14
CUSP STATUS
S
LT
DS15
P16
"
AUXILIARY
OUTPUT POWE
(2A MAX
L1 N/L2
BK UP
DS12
BS UP
DS14
BS DN
DS7
BK DN
DS13
K5
PUMP
DS11
P13
LOCKOUT
DS4
DS16DS17
CB2
CB1
R
)
P12
MAINS
INPUT POWER
L1
P11
P10
R74 R72 R73
N/L2
N/L2
BK UP
BS UP
BS DN
BK DN
P9
PUMP
PUMP
N/L2
)
~
V
240
220
(
#
)
~
T
V
R
A
120
-
P
100
(
P1
P2
S1
TEST POINTS
PRGM
P5
T
DS3DS5
O
P
BK
P4
T
O
SP
2
1
0
3
B
DS1
DS2
#1 #2SETS
ON
O
FF
O
FF
S2
O
N
O
FF
12
O
FF
O
N
P6
O
N
O
N
SP
DS6DS9DS10
BK
S
B
R
E
P
EE
B
85.0812.00, 2003 CH-13
Chairs Electrical Systems Service Parts
Item # Part Number Description
1 61.1332.00 100V, Yellow wires
61.1333.00 120V, Black wires
61.1334.00 240V, Red wires
2 90.1031.00 Capacitor with boot (100-120V)
90.1034.00 Capacitor with boot (240V)
3 041.372.00 Positioning potentiometer
4 61.2065.00 Back up limit switch
5 044.184.01 Base up limit switch
6 61.2099.00 Cable assy, tilt switch
(1040) only
7 61.3043.00 8-button footswitch
8 39.1045.00 Chair touchpad
39.1385.00 Performer touchpad
39.1090.00 Cascade Master with cuspidor
39.1090.00 Cascade Master w/o cuspidor
To Replace Circuit Board P/N Order this kit
61.2510.00 90.1029.00 (100-120V)
61.1214.01
61.1373.01
61.2512.00 90.1029.01(220-240V)
61.1217.01
1
2
3
4
5
6
7
8
21
0
3
CH-14
Chairs Diagnostic LEDs for the Circuit Board
LEDs
NOTE: Refer to Testing Factory Defaults
for more details.
DS1
DS2
DS3
DS7
DS8
DS9
DS10
DS11
DS12
DS13
DS4
DS5
DS6
DS14
DS15
DS16
DS17
R73
R72
R74
85.0812.00, 2003
85.0812.00, 2003 CH-15
Chairs Diagnostic LEDs for the Circuit Board
LED Description Information Communicated
DS1 S2 (red DIP switch) is ON Switch is ON
DS2
DS3 Back Potentiometer LED ON Back potentiometer is functioning normally when the chair back is moving
DS4 Handpiece Lockout LED ON Lockout enabled
DS5 Base Potentiometer LED ON Base potentiometer is functioning normally when the chair base is moving
DS6 Chair Stop Plate Limit Switch LED ON Chair stop plate limit switch activated
DS7 Base Down LED Relay is ON when LED is ON and the function is moving
DS11 Pump LED
DS12 Back Up LED
DS13 Back Down LED
DS14 Base Up LED
DS8 Cuspidor Limit Switch LED ON Cuspidor limit switch activated, or jumper is missing
DS9 Back Up Limit Switch LED ON Back Up limit switch activated
DS10 Base Up Limit Switch LED ON Base Up limit switch activated
DS15 Status LED ON ON: Normal operation
OFF: Microcontroller is not functioning. Verify voltage regulator LEDs
(DS16 and DS17) are ON. Is the chair plugged in? Circuit breaker tripped?
Slow Blink: Check cuspidor (DS8) and stop plate (DS6) limit switch LEDs
Fast Blink: Check handpiece lockout (DS4) LED
Double Blink: A SPARE jumper is in the FACT DEFAULT position
DS16 5V Regulator LED OFF 1. Power to circuit board is OFF, or
2. There is a short in the cable to the base or back potentiometer. Disconnect all cables
except the power cable. Plug the cables in one at a time (the LED will turn ON when the
problem is fixed).
DS17 12V Regulator LED OFF 1. Power to circuit board is OFF, or
2. There is a short in the cable to the status light or limit switch (the LED will turn ON when
the problem is fixed).
85.0812.00, 2003 CH-16
Chairs Chair Printed Circuit Board (PCB)
Testing and
Programming
the Circuit Board
WARNING
The chair will begin to
move automatically
during this test; to avoid
injury or equipment
damage, remove all
possible obstructions and
maintain a safe distance
from the chair. To
interrupt the chair cycle,
press any button on the
touchpad or footswitch,
or activate the chair
stop plate.
Follow these steps to test and program the chair circuit board.
Task Description
1 Insert the SPARE jumper into the FACT DEFAULT location (on P17).
Result: The chair will cycle the base and back movements and automatically
reprogram the memory positions to the factory settings
(position 0 to entry/exit; 1 and 2 to the same pre-programmed positions;
and 3 to cuspidor/return).
If the circuit board beeps three times, continue with step two.
If the circuit board beeps just once, the chair cycle has been interrupted. Diagnose
and correct any errors, then press either circuit breaker for five seconds to restart
the cycle (refer to Testing Factory Defaults).
2Move the jumper from the FACT DEFAULT location (on P17) back to the
SPARE location.
NOTE: The jumper must be in the SPARE position for normal chair functions and
safe operation.
3Press “1” on the touchpad or footswitch, or the green position on the
8-function footswitch.
Result: The chair will move to the operating position.
4Press “0” on the touchpad or footswitch, or the red button on the 8-function
footswitch.
Result: The chair will move to the entry/exit position.
NOTE: The chair programmable position buttons can be reprogrammed to the
desired positions as specified by the dental team.
85.0812.00, 2003 CH-17
Chairs Tests
Problem Action
Factory Default test will not start
(LEDs DS15, DS16 and DS17
are Off)
Factory Default test will not start
(LED DS15 is Off; DS16 and DS17
are ON)
Factory Default test will not start
(LED DS15 is blinking; DS16 and
DS17 are ON)
If . . .
Then . . .
Transformer thermal limiter is open
Circuit breaker is tripped
Wait for transformer to cool off.
Reset circuit breaker (short circuit fault currents
may damage the circuit breaker and prevent it
from resetting).
If . . .
Then . . .
Input voltage is too low or is outside the
required range
Microcontroller is not functioning
Ve rify input voltage and voltage selection
resistors (100-120VAC=R72 and R74)
(220-240VAC=R73).
Replace the circuit board.
If . . .
Then . . .
Input voltage is too low or is outside the
required range
Microcontroller is not functioning
Ve rify input voltage and voltage selection
resistors (100-120VAC=R72 and R74)
(220-240VAC=R73).
Replace the circuit board.
Testing Factory Defaults
The table lists conditions and corrective actions for testing the factory defaults for LEDs.
85.0812.00, 2003 CH-18
Chairs Tests
Problem Action
Factory Default test halts during
the BASE UP test and the PCB
board beeps one time
Factory Default test halts during
the BACK DOWN test and PCB
board beeps one time
If . . .
Then . . .
Input voltage is too low or is outside the
required range
Base Up limit switch is activated
Motor thermal limiter is open, motor is hot
Motor capacitor is defective
Base Up solenoid is defective
Base is in hydrostatic lock
Potentiometer is not changing voltage
Ve rify input voltage and voltage selection
resistors (100-120VAC=R72 and
R74 (220-240VAC=R73).
Verify switch operation.
Wait for motor to cool off.
Test capacitor and replace, if needed.
Test solenoid and replace, if needed.
Refer to Correcting Hydrostatic Lock.
Ve rify potentiometer LED comes ON when base
is moving.
Check potentiometer mechanical drive and
electrical connections.
If . . .
Then . . .
Stop plate limit switch is activated
Stop plate is jammed
Back Down solenoid is defective
Back is in hydrostatic lock
Potentiometer is not changing voltage
Verify switch operation.
Remove and reinstall the stop plate.
Test solenoid and replace if needed.
Refer to Correcting Hydrostatic Lock.
Ve rify potentiometer LED is ON when back
is moving.
Check potentiometer mechanical drive and
electrical connections.
85.0812.00, 2003
CH-19
Chairs Tests
Problem Action
Factory Default test halts during
the BACK UP test
Factory Default test halts during
the BASE DOWN test
Chair moves by itself when power
is turned ON
If . . .
Then . . .
Back up limit switch is activated
Back Up solenoid is defective
Back is in hydrostatic lock
Potentiometer is not changing voltage
Verify switch operation.
Test solenoid and replace, if needed.
Refer to the Correcting Hydrostatic Lock.
Ve rify potentiometer LED is ON when back
is moving.
Check potentiometer mechanical drive and
electrical connections.
If . . .
Then . . .
Stop plate limit switch is activated
Base Down solenoid is defective
Base is in hydrostatic lock
Potentiometer is not changing voltage
Verify switch operation.
Test solenoid and replace if needed.
Refer to Correcting Hydrostatic Lock.
Ve rify potentiometer LED is ON when base
is moving.
Check potentiometer mechanical drive and
electrical connections.
If . . .
Then . . .
The jumper is in FACT DEFAULT position
Short circuit in touchpad or footswitch
Short circuit on circuit board
Verify that the jumper is in the
SPARE position.
Unplug the touchpad and footswitch; reset the
circuit breaker. If the problem isn’t repeated, the
touchpad or footswitch may have shorted.
Replace the circuit board.
Chairs Chair Printed Circuit Board (PCB)
Raise the chair with the
stop plate limit switch
Enable and disable touchpad
and footswitch buttons
Handpiece lockout
Diagnostic LEDs
Test Points Header
Plug the chair into an electrical outlet.
Tap the chair stop plate three times within five seconds and hold on the third tap.
Result: The chair base will continue to rise as long as the stop plate is held in. This function is
automatically disabled after five minutes but is re-enabled upon each power up. To reset the
five-minute timer, depress either circuit breaker until the LEDs turn OFF, then release the
circuit breaker.
Place the SPARE jumper in the EN/DIS TP/FS position of the Test Points header P17.
Push the buttons to be Enabled or Disabled (PRGM, PRGM 0, PRGM 1, PRGM 2, PRGM 3).
Result: One beep indicates the button is disabled. Three beeps indicate the button in enabled.
Place the SPARE jumper back into the SPARE position of the Test Points header P17.
Plumb a normally open air-electric switch ( kit P/N 61.1384.00) to the air-coolant tubing (green with
long white dashes).
Insert the two position connector from the air-electric switch into P13 Lockout (next to the transformer)
See Diagnostic LEDs for the Circuit Board.
Use a SPARE jumper to test the chair manual functions (BKUP, BSUP, BSDN, BKDN).
BK POT and BS POT points allow test meter check of potentiometer voltages and
measurement of the analog DC voltage from pin 2 of the potentiometer.
Feature Programming
The chart provides information on new features and associated programming on the PCB.
CH-2085.0812.00, 2003
Identifying
New Features
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