Forest Dental 3900 User manual

7.13.20  0097-046  Rev. A  4 of 4
Pivot Chair Adapter, Delivery
& Light Installation Instruction
Alert Symbols e safety notices associated with the following should be given special attention when they appear in maintenance,
operating and emergency procedures in the guide.
CAUTION indicates that a particular procedure or precaution must be followed to avoid system irregularity or possible damage to the product.
NOTE indicates special information to improve the ease of maintaining the product, or to clarify important information.
WARNING indicates that the personal safety of the patient, end user or technician could be compromised by disregarding the WARNING.
Not following instructions may result in an injury.
CAUTION: Field modications that alter the electrical and/or mechanical safety of Forest products conict with agency construction le
requirements and are not sanctioned by Forest.
NOTE: Installation Verication: Refer to Operator’s Guide or Service Manual on our website at Forestdental.com; perform all operations.
If operations performing as intended installation complete. If operations not performing as intended, review steps in installation instructions
to conrm correct installation or call Forest Technical Support at 800-423-3555.
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DTE Oregon, Inc.
Address 6200 ne cherry drive hillsboro oregon 97124  USA
Phone 800 . 423 . 3555  503 . 640 . 3012 | Fax 503 . 693 . 9715 | Digital [e-mail] forestdental.com
Forest Dental Equipment
Tools Required: 1/8”, 3/16”, 5/32” & 5/16” Allen Wrenches, 1/8”, & 5/16” Allen Sockets with Torque Wrench, 15/16” Wrench, Standard and
Metric Hex Key Set, Flathead Screwdriver, Bubble Level, and Nitrile Gloves.
1. Place a thrust washer on the bearing surface of the arm pivot pin.
2. Apply lubricant to a thrust bearing and install the bearing, followed by a second thrust washer.
3. Insert arm pivot pin and bearing stack into pivot delivery arm.
4. Position a thrust washer onto the at member of the pivot delivery arm and arm pivot pin.
5. Apply lubricant to the second thrust bearing and install followed by a thrust washer.
6. Insert the arm pivot pin and pivot delivery arm with thrust bearing and washers into the chair
adapter.
CAUTION: To avoid damage to the pivot bushing, do not use force when installing the arm
pivot pin into the pivot delivery arm.
NOTE: Engagement is a slip t, provided the pivot delivery arm is held in alignment.
7. Make sure the arm pivot pin slot faces the side of the pivot delivery arm having the
tapped hole.
8. Seat the bearing assembly until the arm pivot pin is in full contact with the bottom and
sides of the chair adapter.
9. Use 3/8-16 x 2-1/4” hex bolt, lockwasher and at washer to secure arm pivot pin to chair
adapter.
10. Locate the 1/4-20 x 3/4” set screw in the threaded hole on the chair adapter. Tighten the
set screw to prevent the arm pivot pin from rotating.
12. Place a 1/4-20 x 3/8” set screw into the threaded hole in the at end of the pivot delivery arm.
13. Engage the 1/4-20 x 3/8” set screw with a 1/8” hex key to deform the internal bushing
against the arm pivot pin until a 3-pound force is achieved to rotate the pivot delivery arm.
14. Install the pivot cover over the bolt head.
Slot
1/4-20 x 3/4"
Set screw
Counter bore
Thrust washers
1-1/4" Brass bushing
Pivot light/monitor
arm
Arm pivot pin
3/8" Flat washer
3/8" Lock
washer
Thrust bearing
3/8-16 x 2-1/4" Bolt
1/4-20 x 3/8"
Set screw
Pivot cover
Arm stop
Light/Monitor Bearing Assembly
Chair
adapter
Thrust
washers
Thrust bearing
1. Plug in the chair to mains power.
2. Raise the chair base to its upper travel limit and disconnect from mains power.
3. Apply lubricant to both sides of all thrust washers and thrust bearings.
4. Place a thrust washer, bearing and another thrust washer onto the arm pivot pin. Insert the
arm pivot pin and bearing stack through the 1-1/4” brass bushing at the end of the pivot
light/monitor arm. Place another thrust washer, bearing and thrust washer onto the arm
pivot pin.
5. While holding the bearings and arm pivot pin in the pivot light/monitor arm, align the slot
in the arm pivot pin with the chair adapter’s bottom counter bore. Adjust the pivot light/
monitor arm and arm pivot pin so it will slide into the counter bore.
CAUTION: To avoid damage to the pivot bushing, do not use force when installing the arm
pivot pin into the pivot light/monitor arm.
NOTE: Engagement is a slip t, provided the pivot light/monitor arm is held in alignment.
6. Seat the bearing assembly until the arm pivot pin is in full contact with the bottom and
sides of the chair adapter.
7. Make sure the arm pivot pin slot faces the side of the light/monitor arm having the tapped hole.
8. While holding the pivot light/monitor arm in position, install the 3/8-16 x 2-1/4” hex bolt
with 3/8” lock and at washers through the arm pivot pin so that it threads into the chair
adapter. Tighten the bolt enough to remove most of the clearance between the bearings.
9. Install the 1/4-20 x 3/4” set screw into the threaded hole on the pivot light/monitor arm.
Tighten the set screw to prevent the arm pivot pin from rotating.
10. Finish tightening the bolt in the arm pivot pin until all the clearance between the bearings
are eliminated and the pivot light/monitor arm move freely. Tighten the set screw.
11. Place the 1/4-20 x 3/8” set screw into the threaded hole of the at end of the pivot light/
monitor arm.
12. Engage the 1/4-20 x 3/8” set screw with a 1/8” hex key to deform the internal bushing against
the arm pivot pin until a 3-pound force is achieved to rotate the pivot light/monitor arm.
13. Install the pivot cover over the bolt head.
Delivery Bearing Assembly
3/8-16 x 2-1/4” Hex bolt
3/8" Lock washer
3/8" Flat washer
Arm pivot pin
Thrust washers
Pivot delivery
arm
Slot
1/4-20 x 3/8"
set screw
1/4-20 x 3/4"
set screw
Thrust bearing
Chair adapter
Pivot cover
Post stop
Thrust washers
Thrust bearing
Tapped hole
Tapped hole
1. Plug in chair to mains power.
2. Raise the chair base and back to full up position.
3. Unplug the chair from the mains power.
NOTE: Skip steps 4-7 if chair adapter is already installed.
Chair Adapter Installation
5. Slide lip of the washer onto lip of the chair.
6. Install the 15/16” mounting bolt loosely into
the back of the mount and into the chair.
Underside of
chair adapter
Leveling
set
screws
(3)
Mounting
bolt and
washer
Leveling set
screw holes (3)
Mounting
bolt
Lip of chair
Slide washer over lip of chair
Chair adapter
installed
4. Position the chair adapter so that the lip of the chair rests
underneath the lip of the washer. e mount will hold
itself in place.
7. Place a level on the chair adapter, parallel with and perpendicular to the chair center line.
8. Verify the chair adapter is level.
NOTE: If leveling is necessary, adjust the 3/16” set screws (3) until the unit chair adapter is level.
9. Tighten 15/16” mounting bolt (55 foot-pounds).
NOTE: Verify steps 7, 8 and 9 aer unit and light are installed. Re-level if necessary.

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CAUTION: A base down stop is not likely installed on your exsisting chair if a pivot light is being added aermarket. One must be installed if the
pivot light is attached to the bottom of the chair adapter (refer to page 4, Light/Monitor Bearing Assembly). Failure to install the appropriate down stop
may result in the motor pump cover being damaged when the chair is positioned full base down.
3900 Chair Lift Stop/Spacer Installation
1. If stop was installed at Forest,
proceed to bottom of page 3,
Level Delivery and Light Pivot
Post(s).
Safety plate
Base Down Spacer/Stop
Level Delivery and Light Pivot Post(s)
1. Install bearing assemblies (refer to page 4).
2. Level pivot posts with bubble levels.
3. Reinstall chair covers aer delivery and/or light is installed
by reversing steps 1-5 in “Removing Chair Covers” section.
Mounting bolts
Set screws
Check leveling after
all loads are in place.
5. Install the appropriate base down stop over the li cylinder rod.
6. Ensure the stop straddles the vent tube.
7. Reinstall the safety stop plate.
(4) Screws
( 2 on each side)
CAUTION: A wire is connected to the indicator light. Be sure not to pull cover completely o before next step.
3. Li upper cantilever cover o the chair li frame.
4. Press release clip to disconnect wire.
Wire
connector
release
clip
No washers
2” spacer on chairs
after 7/8/13
1.75” spacer on chairs
pre 7/8/13
.50” spacer on chairs after 3/17/15
.75” spacer on chairs after 8/1/20
Brass and
plastic washers New
conguration
Removing 3800 Chair Covers and Installing Lift Stop
Pump
cover Screws (2)
CAUTION: A wire is connected to the indicator light. Be sure not to pull cover completely o before next step.
4. Li upper cantilever cover o the chair li frame.
5. Press release clip to disconnect wire.
10. Install stop on top of base cylinder.
Wire
connector
release
clip
1. Using a 1/8” hex key, remove
the screws (2) on the sides
of the pump cover.
Tabs and
brackets(2)
Lift pump cover
2. Slide pump cover forward and li front tabs over brackets (2)
to remove pump cover.
2. Using a athead screwdriver,
remove shoulder bolt and
safety stop plate.
3. Turn rear side covers (2)
counter clockwise to remove.
6. Using a 5/32” hex key, remove the
screws (2) on each side of the upper
rear cover.
7. Remove upper rear cover.
CAUTION: A wire is connected to the memory button. Be sure not to pull cover completely o before
performing the next step.
8. Disconnect the memory button wire connector by pressing the release clip.
Remove upper rear cover.
9. Using both hands, spread the safety stop plate and pull outward to li cover
over bolts on each side. Remove cover.
Memory button
wire connector
Bolts (2)
Wire
connector
release
clip
Shoulder bolt