3900 Dental Chair Service Manual
Contents
1. C Z I T j O o TEE i B Motor Start Run Capacitor 45uf 3912 028 Motor Si 8 8 2011 Rev 0097 381 Page 9 Model 3900 Dental Chair Solenoid Manifold Assembly Part Description Number 3914 047 Solenoid Manifold Assy 110VAC complete with 4 solenoids 3914 049 Solenoid Manifold Assy 230VAC complete with 4 solenoids 3914 050 Solenoid Single 3900 110VAC 3914 051 Solenoid Single 3900 230VAC n Kach 8 8 2011 Rev 0097 381 Page 10 Model 3900 Dental Chair Removing a Faulty Solenoid The following steps will guide you through the process of removing a faulty solenoid A WARNING A The solenoids are powered by mains voltage 120 or 240 VAC Failing to unplug the chair from mains voltage may result in serious injury from electrical shock Task Procedure 1 To depressurize the chair hydraulic system lower the base and back to full down Remove the motor EI pump cover and unplug the chair 2 Remove the two screws that secure the manifold to the chair hydraulic tray Turn the manifold to access the solenoids SLREME 3 Using a Philips screwdriver remove the faulty solenoid coil 4 Cut the faulty solenoid wires approximately 4 from the solenoid Discard the faulty solenoid 5 Remove the solenoid stem and o ring from the manifold cavity er RETAINING SCREW E WASHER AND LOCK Refer to page 12 for installation instruc2. Using a Touch Pad to set the Hard Limits 1 Locate the P program button on the touchpad 2 Press and HOLD the P button Two beeps will be heard 8 8 2011 Rev 0097 381 Page 19 Model 3900 Dental Chair 3 With the P button STILL HELD DOWN use the manual 6 Press Button 1 you will hear three beeps BASE UP function to position chair base to the desired base up limit 7 Repeat steps 1 6 for Base Down Back Up and Back Down For step 6 substitute the appropriate numbered button for the function travel limit being programmed 4 Once the desired base up position has been reached RELEASE all control buttons 5 Press and release the Program button you should hear two beeps a Base Up Press 1 b Base Down Press 2 c Back Up Press 3 d Back Down Press 4 NOTE These sequences should be done within 1 second of each other If multiple beeps are heard the programming was not accepted Beginning with step 1 try programming the travel limit again 8 Once programming is complete return the dip switches to the OFF position 9 Manually operate the chair base up down back up down to confirm the limits were programmed 10 Reinstall motor pump cover on the chair 8 8 2011 Rev 0097 381 Page 20 Model 3900 Dental Chair Using a Footswitch to set the Hard Limits 4 Locate the M button on the top of the rear cantilever cover 1 Remove the motor pump cover to acc
3. SU FUTT m forest dental www forestmed com affordable excellence designer friendly 08 08 11 Rev 0097 381 COPYRIGHT WARRANTY TRADEMARKS 201 1 BY FOREST DENTAL PRODUCTS INC 6200 NE CAMPUS COURT HILLSBORO OR 97124 PRINTED IN U S A FOREST DENTAL PRODUCTS WARRANTS ITS PRODUCTS TO BE FREE FROM DEFECTS IN MATERIAL AND WORKMANSHIP ONLY NO OTHER WARRANTIES ARE EXPRESSED OR IMPLIED THIS WARRANTY SHALL EXTEND FOR FIVE YEARS UNLESS OTHERWISE STATED WRITTEN NOTICE OF BREACH MUST BE GIVEN TO FOREST DENTAL PRODUCTS WITHIN THIS PERIOD BUYERS REMEDY FOR BREACH OF THIS WARRANTY IS LIMITED TO REPAIR PARTS OR REPLACEMENT OF ITEMS BY FOREST DENTAL PRODUCTS INC THIS WARRANTY IS VOID IF ITEMS ARE CARELESSLY USED OR IMPROPERLY MAINTAINED OR INSTALLED THIS WARRANTY DOES NOT COVER DAMAGE THAT RESULTS FROM USING CLEANING DISINFECTING OR STERILIZATION CHEMICALS AND PROCESSES THIS WARRANTY DOES NOT COVER LIGHT BULBS HANDPIECE ILLUMINATION AND HEATED SYRINGE TUBINGS ARE WARRANTED FOR SIX MONTHS TO BE FREE FROM DEFECTS IN MATERIAL AND WORKMANSHIP ONLY FACTORY REPAIRS ARE COVERED FOR A PERIOD OF 90 DAYS NO CLAIM FOR LABOR OR CONSEQUENTIAL DAMAGES WILL BE ALLOWED FOREST LOGOS ARE REGISTERED TRADEMARKS IN THE U S PATENT AND TRADEMARK OFFICE WELCOME WELCOME TO THE 2011 EDITION OF THE FOREST 3900 DENTAL CHAIR PARTS AND SERVICE MANUAL THIS MANUAL IS AN EASY TO USE SOURCE OF TECHNICAL INFORMATION FOR SERVICING THE
4. 2 Using the manual positioning buttons on the Footswitch position the chair base and back to the new position 3 Press and release the M button you will hear two beeps Within 1 second press the button 0 I IT or III you want to assign the position to You will hear three beeps confirming the new position for that button has been accepted 4 Check the new programmed position by manually moving the chair base and back to another position Press the button you just assigned a new position to and the chair should move to the new position programmed in step 3 ennen ph ENG eg Me dE Me Meet eg ks 8 8 2011 Rev 0097 381 Page 24 Model 3900 Dental Chair Running the Self Test The chair Self Test will cycle the chair base and back up down If the chair stops either the base or back and beeps once the test has detected a fault that will require diagnosis and adjustment or repair The test cycles the chair until a full base up full back down to A WARNING A full base down full back up cycle is achieved If the test was successful the chair will beep three times 3 Move both DIP switches to the ON position The chair will move base up down back up down during To run the test this test To avoid personal injury or damage to other 1 Remove the motor pump cover to access the chair equipment remove all possible obstructions from the circuit board area of the chair and keep a safe distance from the 2 Loca
5. Alternatively you can wait 20 30 minutes for the pump to cool and resume working If after cooling down the pump starts running on its own the motor pump relay has failed remove and replace the chair circuit board 8 8 2011 Rev 0097 381 Page 28 Model 3900 Dental Chair Faulty base or back down 1 Verify that the resistance of the solenoid coil is SCENE a 100 120 VAC 200Q b 220 240 VAC 464Q 2 Replace the base or back down solenoid assembly Base or back DOWN function inoperative WARNING Depressurize the chair hydraulic system before removing the solenoid Switch the working down solenoid coil with the faulty solenoid coil to position the chair full base back down 8 8 2011 Rev 0097 381 Page 29 Model 3900 Dental Chair Faulty foot switch or touch pad 1 Try using the touch pad or footswitch connector ANI AN4 pins on the circuit board to test the chair manual functions as follows FUNCTION 1to6 BASE UP 1to7 BACK UP 2t07 BACK DOWN 4to7 BASE DOWN 2 If the manual functions work the foot switch touch pad or wiring harness is faulty 3 If the chair is equipped with multiple foot switches touch pads or a combination of them try connecting one at a time until you isolate the faulty one 8 8 2011 Rev 0097 381 Page 30 Model 3900 Dental Chair Faulty touchpad 1 Disconnect the touchpad wiring harness from the back of the touchpad a To acce
6. 1 Page 34 Model 3900 Dental Chair Base Position Sensor Task Procedure 1 Remove the motor pump cover from the chair 2 Position the chair base full base down 3 Loosen the bracket screws until you are able to disengage the gears Turn the small gear on the pot shaft in the base down 4 direction until it stops Then turn in the base up direction three teeth on the small gear relative to one tooth on the big gear Engage the gears and tighten the bracket screws Refer to Setting Hard Limits DOWN 7 rm A sS SMALL BRACKET GEAR 5 SCREWS NOTE The front lift arm cover is removed for clarity and it is not necessary to remove the cover to complete this procedure 8 8 2011 Rev 0097 381 Page 35 Model 3900 Dental Chair Parts Breakdown Base Positioning Sensor and Drive 1 3914 042 Potentiometer 3900 Chair Position Sensor Base or Back 3912 017 Wiring Harness Base Pos Sensor 3914 043 Base Potentiometer Gear Small 3914 037 Base Potentiometer Gear Large Base Potentiometer Assy 3900 ee includes items 1 and 3 Le BLACK YELLOW Wiring Harnesses Part Number Description 3912 016 Wiring Harness Safety Switches 3912 015 Wiring Harness with Switch Manual Override 3912 014 Wiring Harness Indicator Light 8 8 2011 Rev 0097 381 Page 36 Model 3900 Dental Chair Back Positioning Sensor and Drive eoe TT includes items 3 4 and 7 hem PartNumber Dese
7. 3900 3914 010 G SH Foot Switch 3900 Chair specify color 3914 032 Cable Touch Pad Lower Unit 96 long 3900 i Cable Touch Pad Upper Unit 132 4 3914 031 long 3900 Cable Touch Pad Chair Mounted 9914 090 Touch Pad 60 long 0014 331 Harness Remote Touch Pad 25 long 3914 042 Potentiometer 3900 Chair Position Sensor Base or Back 3912 018 Wiring Harness Back Pos Sensor 2 3912 017 Wiring Harness Base Pos Sensor 3914 044 Base Potentiometer Assy 3900 3914 043 Base Potentiometer Gear Small 3912 025 Switch Safety Plate 3900 3912 016 Wiring Harness Safety Plate 115VAC Fuse Kit 5x20mm includes 3914 040 two 250V 10A fuses and one 250V 7 125mA fuse 230V Fuse Kit 5x20mm includes two 3914 035 250VAC 6 3A fuses and one 230V 63mA fuse 3914 050 Solenoid Single 3900 110VAC Solenoid Manifold Assy 3900 3914 049 230VAC 3914 051 Solenoid Single 3900 230VAC 8 8 2011 Rev 0097 381 Page 18 Model 3900 Dental Chair Testing and Programming the Chair Setting Hard Limits This programming operation should be performed by a qualified service technician or authorized Forest representative Each travel limit can be set individually 1 Remove the motor pump cover to access chair circuit board 2 Locate the DIP switches on the top left hand corner of the circuit board a his is a small red block labeled SW with two white switches 3 Move both DIP switches to the ON position
8. FOREST MODEL 3900 DENTAL CHAIR INTENDED AUDIENCE THIS MANUAL IS INTENDED FOR NEWLY TRAINED AND EXPERIENCED DENTAL EQUIPMENT REPAIR TECHNICIANS WE ASSUME YOU UNDERSTAND THE OPERATION OF DENTAL EQUIPMENT AND CAN FOLLOW FLOW DIAGRAMS 8 8 2011 Rev 0097 381 Page 2 TABLE OF CONTENTS PAGE OVERVIEW SERVICE AND SUPPORT 4 LOCATING THE MODEL SERIAL NUMBER 5 POWER ON INDICATOR 5 REMOVING AND INSTALLING CHAIR COVERS 6 THE HYDRAULIC SYSTEM 7 FLOW DIAGRAM 8 SERVICE PARTS 9 SOLENOID MANIFOLD ASSEMBLY 10 REMOVING A FAULTY SOLENOID 11 INSTALLING A NEW SOLENOID 12 ADJUSTMENTS 13 CHAIR ELECTRICAL SYSTEM 15 CIRCUIT BOARD 16 DIAGRAM 17 SERVICE PARTS 18 TESTING AND PROGRAMMING THE CHAIR 19 SETTING HARD LIMITS 19 PROGRAM CHAIR AUTO POSITIONING FUNCTIONS 23 RUNNING THE CHAIR SELF TEST 25 TROUBLESHOOTING 26 ADJUSTING THE POSITION SENSING POTENTIOMETERS 33 PARTS BREAKDOWN 35 SPECIFICATIONS 39 DIMENSIONS 40 8 8 2011 Rev 0097 381 Page 3 Model 3900 Dental Chair OVERVIEW The Forest Model 3900 Dental Chair is an electronically ON controlled hydraulically powered chair The Touchpad and j Footswitch are used to position the chair and program kd auto positioning functions into the chair The chair hydraulic system is controlled by the electronics using electro mechanical relays and electrically powered solenoid valves This section provides information related to locating the chair model serial number servicing the chair troubles
9. I d JO OOULR HSV AN6 VSS F5V AN7 VSS Bed Led dWNd HOLOW NMOG 3S V8 e HEDE W s INDE AN13 AN14 AN15 e G Il 9 Li Cc CN2 POWER INPUT BACK Fy CN1 230VAC 250VAC Gs 115VAG 125VAC 10A ERC END I d JC ME If 250VAC 63 mA 115VAC RV1 471 221 AC 230V 115V dN MOV NMOd Vd aay P 230VAC 250VAC 63 mA 115VAC 125VAC 125mA 8 8 2011 Rev 0097 381 Page 16 Model 3900 Dental Chair Diagram Rn H Fforest TO MOTOR PUMP d TOUCH PAD NOT M USED 0000 Vi wl BUTTON x NI CAPACITOR A H 45 uF POWER ON 1 SOLENOID MANIFOLD INDICATOR ee ASSEMBLY sell a E gt 5 OWER INPUT X iu f Mi z C6 m T f CN A d mm e BR I iC 10 NJ Z r i p A RLIGH r3 1 EH ANG F2 Le t 2S0VAC 63 mA wm mm vm I CNG 115VAC hj c ccs 125 WAL 25m UP ANS WA WA date I r AV 138 dN MOV FOOT SWITCH AV 138 NMOQ ASV NMOQ Vd BACK e POSITION BS T SENSOR sk om BED LL FETTETTETTETTETTETTT BASE POSITION SENSOR SAFETY STOP SK OHM LIMIT SWITCHES 8 8 2011 Rev 0097 381 Page 17 Model 3900 Dental Chair Service Parts Item Part Number 9 3912 005 Wire Harness with Switch 3914 011 Command Control Board 3900 Chair 3914 014 Wire Harness Light 110V 1 Command Control Board 3900 Chair 3914 012 220V 3914 015 Membrane Switch Touch Pad
10. W FINE SINTER COM 3 s aga 8 8 2011 Rev 0097 381 Page 14 Model 3900 Dental Chair Chair Electrical System Description HERI Back Up Down Solenoids Out HERI Mains Power In 115VAC 125V 50 60Hz The Forest Model 3900 Dental Chair circuit board has the Fuse F1 and F2 115V 10A 5x20mm relays necessary for controlling the chair motor pump and 10 Fuse F1 and F2 230V 6 3A 5x20mm solenoids The circuit board is also equipped with a test Circuit Board function that allows verification of the chair functions without a Motor Pump and Solenoid Relays foot switch or a touchpad Fuse F3 115V 125mA 5x20mm 12 To access the chair circuit board remove the motor pump Fuse F3 230V 63mA 5x20mm cover AN12 AN15 Jumpers installed do not remove NOTE Any circuit board components not identified are not LED1 LEDS Illuminate when associated relay is being used or are non functional energized Base and Back Position Sensors 15 AN6 Back Position Sensor Em AN7 Base Position Sensor SW Dual switch DIP used to function e Enable programming the chair hard limits AN10 Safety Plate Switches e Enable initiation of the chair self test m AN10 Test Jumper P N 0014 287 Used to short Normally both switches are OFF AN10 Base Up Down Solenoids Out 8 8 2011 Rev 0097 381 Page 15 Model 3900 Dental Chair e SND Bi YNI LNdLNO xnw YOLOW dWNd CN7 LIGHT 3 uH Em REY6
11. d at any chair position pinched Debris in the pump or the pump Replace the motor pump assembly is damaged Chair base or back drifts down V down solenoid Replace the faulty solenoid slowly Faulty solenoid manifold Replace the faulty check valve assembly check valve 8 8 2011 Rev 0097 381 Page 33 Model 3900 Dental Chair Adjusting the Position Sensing Potentiometers Back Position Sensor Task Procedure Position the chair back fully down then remove the seat upholstery from the chair Using a 1 5mm hex key loosen the brass helical drive shaft to pot shaft coupler setscrew then move the chair back up down to expose the second coupler setscrew and loosen it as well 3 Position the chair back fully up Using a 3mm hex key remove the helical drive shaft ii anchor bracket 5 Carefully pull the helical drive shaft blue tube and S d SE brass coupler off the pot shaft E BACK DOWN e Turm the pot shaft clockwise until it stops then E NEU rox counterclockwise 1 8 of a turn gt HELICAL 7 Carefully push the helical drive shaft blue tube and brass coupler onto the pot shaft Using a 1 5mm hex key tighten the brass coupler 8 setscrew Then move the chair back up down to expose the second coupler setscrew and tighten it as well 9 Using a 3mm hex key reinstall the helical drive shaft anchor bracket 10 Reinstall the seat upholstery on the chair 11 Refer to Setting Hard Limits 8 8 2011 Rev 0097 38
12. ess chair circuit board 2 Locate the DIP switches on the top left hand corner of the circuit board a his is a small red block labeled SW with two white switches 3 Move both DIP switches to the ON position 5 Press and HOLD the M button Two beeps will be heard 6 With the M button STILL HELD DOWN use the foot switch BASE UP function to position the chair base to the desired base up limit 8 8 2011 Rev 0097 381 Page 21 Model 3900 Dental Chair 7 Once the desired base up position has been reached RELEASE the control buttons Press button 0 and you will hear three beeps Press and release the M button you will hear two beeps 10 Repeat steps 1 6 for Base Down Back Up and Back Down For step 6 substitute the appropriate foot switch button for the function travel limit being programmed e Base Up Press 0 f Base Down Press I g Back Up Press II h Back Down Press III NOTE These sequences should be done within 1 second of each other If multiple beeps are heard the programming was not accepted Beginning with step 1 try programming the travel limit again 11 Once programming is complete return the circuit board dip switches to the OFF position 12 Manually operate the chair base up down back up down to confirm the limits were programmed 13 Reinstall motor pump cover on the chair 8 8 2011 Rev 0097 381 Page 22 Model 3900 Dental Cha
13. ety Plate Retaining Screw Motor Pump Cover Using a 5 32 hex key remove the two button head screws from each side of the cover and lift it Small Arm Cover Using a 7 64 hex key remove the four button head screws from the cover Safety Plate Using a flat tip screwdriver remove the single screw from the safety plate The Safety Plate will drop when the screw is removed E Part Number Description 3912 030 G Motor Pump Cover Gray 3912 030 SH Motor Pump Cover Shadow Screw 3912 011 ma 3910 028 G Small Arm Cover Gray 2 3910 028 SH Small Arm Cover Shadow Small Arm Cover Gray 1 1 4 Hole 3910 029 G for 1090 Umbilical Small Arm Cover Shadow 1 1 4 3910 029 SH Hole for 1090 Umbilical Small Arm Cover Gray 2 Hole for 3910 030 G 1590 Umbilical 8 8 2011 Rev 0097 381 Page 6 Model 3900 Dental Chair THE HYDRAULIC SYSTEM The hydraulic system consists of Tem Description Description performs a number of functions in the A solenoid manifold assembly that controls dental chair hydraulic system the flow of hydraulic fluid to and from the Fluid storage chair cylinders using electrically operated Separation of air from fluid valves The assembly includes four speed control valves used to restrict the flow of fluid to and from the cylinders controlling Settling of contaminants the chair s rate of travel up and down The The fluid level in the reservoir can be seen assembly al
14. hooting and adjustments that can be made to the chair Service and Support Given the proper care the Forest Model 3900 Dental Chair will provide years of trouble free service If something does go wrong with the chair and you are unable to correct the problem call Forest Dental Products Customer Service 800 423 3555 When you call be prepared to provide the following 1 Serial number and if known the approximate date the chair was purchased 2 Symptoms of the problem 3 What steps you have taken towards correcting the problem 8 8 2011 Rev 0097 381 Page 4 Model 3900 Dental Chair Locating the Model Serial Number The model serial number tag identifies the chair as being manufactured by Forest Dental Products and allows Customer Service to determine when the chair was Power ON Indicator manufactured The date of manufacture is very important in determining the chair warranty status as well as the engineering revision The Power ON Indicator when illuminated indicates that the chair has mains electrical power available POWER ON M P INDICATOR SERIAL NUMBER TAG Md SS CONSER 8 8 2011 Rev 0097 381 Page 5 Model 3900 Dental Chair MOINS Insialimg Cham SANA for 1590 Umbilical 3912 031 G Safety Plate Gray includes item 4 The Forest 3900 chair motor pump small arm cover and safety plate covers are removed as follows 3912 031 SH Safety Plate Shadow includes item 4 Saf
15. ir Using the Touchpad to Program the Chair Auto positioning Functions To position the chair to a user programmed operating position press any one of buttons 1 4 on the Touchpad The chair will automatically position its base and back to the programmed base and back positions assigned to that button To change the programmed position assigned to a button 1 Locate the Program button on the Touchpad 2 Using the manual positioning buttons on the Touchpad position the chair base and back to the new position 3 Press then release the Program button you will hear two beeps Within 1 second press the button 1 2 3 or 4 you want to assign the position to You will hear three beeps confirming the new position for that button has been accepted 4 Check the new programmed position by manually moving the chair base and back to another position Press the button you just assigned a new position to The chair should move to the new position programmed in step 3 8 8 2011 Rev 0097 381 Page 23 Model 3900 Dental Chair Using the Footswitch to Program the Chair Auto positioning Functions To position the chair to a user programmed operating position press any one of buttons O III on the Footswitch The chair will automatically position its base and back to the programmed base and back positions assigned to that button To change the programmed position assigned to a button 1 Locate the M button on the chair
16. is faulty Isolate the faulty switch by reconnecting one of the switches to the harness If the chair does not function the switch connected to the harness is faulty if the chair functions the switch that is not connected is faulty b If the chair does not function the wiring harness is faulty Replace the safety plate wiring harness 8 8 2011 Rev 0097 381 Page 27 Model 3900 Dental Chair Disconnected or faulty motor 1 Verify the back and base UP relays click and LEDs 2 and 4 pump start run capacitor illuminate AX wane AX The motor pump start run capacitor may have mains power present at its connections unplug the chair before proceeding Discharge the capacitor with an insulated screw driver placed across the capacitor terminals before disconnecting or connecting the terminals The chair pace and back UP 2 Check the motor pump start run capacitor for loose or broken functions do not work The eouneevens pump motor relay clicks Replace or repair any faulty connections NE 3 Replace the capacitor with one of the correct specifications The chair base and back l p p p l A EONS WAN Over heated hydraulic pump The hydraulic pump motor is equipped with an auto resetting motor thermal limiter the limiters function is to protect the motor from damage if the motors duty cycle is exceeded To check for an over heated pump carefully place your hand on the top of the pump The pump should only be warm not hot
17. l Voltage 5VDC Touchpad Controls Foot Switch UL60601 1 CAN CSA C22 2 No 601 1 Certifications EN60601 1 EN60601 2 amp ISO 6875 1997 MECHANICAL Minimum installation space Base plate footprint Total lift capacity Maximum patient weight Delivery system capacity Weight chair alone Shipping weight Shipping package dimensions 10 ft x 10 ft 3m x 3m 35 x 25 90cm x 65cm 450Ibs 225kg 300lbs 136kg 125lbs 57kg 300lbs 136kg 396lbs 160kg 57 L x 32 H x 34 W 145cm x 81cm x 86cm 8 8 2011 Rev 0097 381 Page 40 Model 3900 Dental Chair DIMENSIONS 3077 21 3 4 552 mm 27 1 4 692 mm between armrests EU x AA f I 30 21 36 533 mm 914 mi y 73 1854 mm 216 mm 381 mm 8 8 2011 Rev 0097 381 Page 41 Model 3900 Dental Chair DIMENSIONS 15 1 2 394 mm 1854 mm 8 8 2011 Rev 0097 381 Page 42
18. nders BACK DOWN BASE DOWN E CAUTION E Never completely close a Throttle Valve the motor pump may overheat possibly damaging the pump motor Do not completely remove a Throttle Valve from the manifold Turn the Base TV3 Clockwise to decrease speed Counterclockwise to increase speed Turn the Base TV4 Clockwise to decrease speed AI 12 Te Adjust Base Up Speed Adjust Base FINE SINTER CO LTD WWW FINE SINTER COM Down Speed E 0 Counterclockwise to increase speed Turn the Back T V2 Clockwise to decrease speed BACK UP BASE UP Counterclockwise to increase speed Turn the Back T V1 Clockwise to decrease speed Counterclockwise to increase speed Adjust Back Down Speed Adjust Back Up opeed 8 8 2011 Rev 0097 381 Page 13 Model 3900 Dental Chair Adjusting the Pressure Relief Valve The pressure relief valve is a spring operated loaded safety device that relieves hydraulic fluid overpressure in the chair hydraulic system If excessive pressure develops in the chair hydraulic system the pressure relief valve will open routing fluid to the reservoir An incorrectly adjusted pressure relief valve may result in a condition known as hydrostatic lock or ay the chair not being able to lift the patient To adjust the valve turn it clockwise until it seats then n counterclockwise 1 1 2 turns Pressure Relief MODEL SVU2N A115 12 Valve d Gi LA O FINE SINTER CO LTD WW
19. ription yy Anchor Bracket NEN Potentiometer Shaft Yoke Block Kit Left and Right 3900 mM pel includes items 5 and 6 5 Yoke Block Right Side 6 YokeBlock Left Side 7 Potentiometer Coupler 1 3914 042 Potentiometer 3900 Chair Position Sensor Base or Back 3912 018 Wiring Harness Back Pos Sensor Ee BLACK YELLOW 8 8 2011 Rev 0097 381 Page 37 Model 3900 Dental Chair Swivel Brake mE 3912 019 e Brake Kit 3900 includes items 1 Brake Handle Cap Screw _ 2 BrakeHande AA 3 Roller Bearing and Races 4 Bearing Cup Upper Brake Pad MENS Lower Brake Pad Stop Lock BRAKE PLATE 8 8 2011 Rev 0097 381 Page 38 Model 3900 Dental Chair Headrest Glide Bar Friction Mechanism 3912 032 Headrest Glide Bar Friction Kit includes items 1 7 1 Sorews6eah gt 2 Lock Washer 6 each 8 FlatWasher 6 each Headrest Slide Kit 3910 025 Contains 1 friction pad and two spacers EI Friction Pad Pressure Plate GN Pressure Plate Spring 2 each 7 Glide Bar Plate 2 each 8 8 2011 Rev 0097 381 Page 39 Model 3900 Dental Chair Specifications ELECTRICAL Classification Class 1 Type B Operation Mode Duty Cycle Intermittent 25 sec ON 300 sec OFF 115VAC 10 4 8A 50 60 Hz Supply Voltage 230VAC 10 2 0A 50 60 Hz 115VAC F1 F2 10A F3 100mA Fuses Type M 230VAC F1 F2 6 3A F3 63mA Contro
20. so includes an adjustable through the sides of the reservoir the pressure relief valve and two check valves reservoir is serviced via a top fill cap Dissipation of heat Hydraulic cylinders that convert hydraulic fluid pressure to mechanical movement lifting the chair base and back Springs and gravity retract the cylinder rods for down movements chair hydraulic pump that is driven by a thermally protected electric motor The pump provides fluid under pressure to the cylinders 8 8 2011 Rev 0097 381 Page 7 Model 3900 Dental Chair Flow Diagram DIS EE V 7 c C 8 8 2011 Rev 0097 381 CYLINDER VENT TUBES MOTOR START RUN CAPACITOR Page 8 Model 3900 Dental Chair Service Parts 3910 021 Back Tilt Cylinder 3900 Chair 3910 020 Base Lift Cylinder 3900 Chair Hydraulic Motor Pump 3900 Chair 3912 026 110VAC Hydraulic Motor Pump 3900 Chair 230VAC 3912 027 Motor Start Run Capacitor 14uf 3912 029 230VAC 3910 001 Hydraulic Fluid Reservoir 3900 Chair Hydraulic Fluid Reservoir 3900 910 002 Chair with 16 oz Hydraulic Fluid 3914 047 Solenoid Manifold Assy 110VAC 3914 050 oolenoid Single 3900 110VAC 3914 049 Solenoid Manifold Assy 230VAC 3914 051 Solenoid Single 3900 230VAC Elbow Fitting Hydraulic Cylinder Cc Ziel Relief eed 4 sum gt ED CYLINDER Jr VENT TUBES Tt
21. ss the touchpad wiring harness to switch membrane connection in the touchpad housing remove the four Phillips head screws from the back of the housing WIRE COLOR FUNCTION When using a touchpad the Black to Brown BASE UP Chair will not move Black to Green BACK UP Black to Yellow BACK DOWN Black to Red BASE DOWN 2 Short the wires on the wiring harness connector as indicated in the table above to test the chair manual functions 3 If the manual functions work the touch pad is faulty if the manual functions do not work the wiring harness is faulty 8 8 2011 Rev 0097 381 Page 31 Model 3900 Dental Chair The position sensing 1 Check the potentiometer connections AN6 and AN7 on the potentiometer for that movement circuit board and the connections at the potentiometer is disconnected 2 Reconnect the potentiometers found to be disconnected The position sensing Visually examine the wiring and connectors for damage potentiometer wiring or connections are faulty The position sensing 1 Across pins 1 3 check the resistance of the potentiometer otentiometer for that movement i Base up down is inoperative eh tailed a 5K Ohm 20 or back up down is 2 Additional measurements of potentiometer resistance can be inoperative made as follows a Measure the resistance across pins 1 2 write down your results b Measure the resistance across pins 2 3 write down your results c Total
22. te the DIP switches on the top left hand corner of chair To force the test to stop press any button on a the circuit board foot switch or touch pad You may also activate the safety stop plate to stop the self test i This is a small red DIP switch labeled SW with two white switches 4 Press the AN TEST button next to the DIP switch on the chair circuit board While the test is running the chair will beep once every second 5 Ifthe test stops and the chair beeps once refer to the troubleshooting section 6 When the test completes successfully the chair will beep three times Return the DIP switch switches to the OFF position and reinstall the motor pump cover 8 8 2011 Rev 0097 381 Page 25 Model 3900 Dental Chair Troubleshooting These tables contain tests and procedures for troubleshooting the most common chair problems These tables are not intended to cover every situation but do include the most common problems you will encounter To effectively diagnose and repair a chair problem you must define the problem as precisely as possible What are the symptoms of the problem Is it a problem with the chair hydraulics electronics or is it user related Table 1 Chair Troubleshooting The chair is unplugged 1 Verify power is available at the outlet 2 Connect the chair to the power outlet F1 F2 or F3 fuse on the chair 1 Check the fuses and replace if blown refer to pages 16 and circ
23. tions WASHER 8 8 2011 Rev 0097 381 Page 11 Model 3900 Dental Chair Installing a New Solenoid The following steps will guide you through the process of installing a new solenoid A WARNING A The solenoids are powered by mains voltage 120 or 240 VAC Failing to unplug the chair from mains voltage may result in serious injury from electrical shock Task Procedure 1 Install the new solenoid o ring and stem in the POPPET gt manifold cavity EI 2 Using a Philips screwdriver install the new solenoid Coil 3 Connect the stripped wires from the new solenoid to SLEEVE the stripped wires from the chair circuit board with the two wire nuts provided 4 Reinstall the manifold assembly to the chair hydraulic tray Plug in the chair and test all chair functions Carefully inspect the manifold for any hydraulic oil leakage if none is found reinstall the motor pump cover RETAINING SCREW WASHER AND LOCK WASHER 8 8 2011 Rev 0097 381 Page 12 Model 3900 Dental Chair Adjustments CV1 and CV2 Check Valves Adjusting the Rate of Travel When the chair base or back are positioned up the CV1 and CV2 check valves will prevent the chair base or back The hydraulic manifold assembly includes four speed control from drifting down until a down solenoid is opened Throttle Valves TV1 TV2 TV3 and TV4 Each TV function meters the flow of hydraulic fluid to and from the hydraulic cyli
24. uit board has failed 18 for the location of the fuses A WARNING A a Chair is inoperative office has The fuses have mains power POWEL present at the fuse holders b unplug the chair before removing or installing fuses T d e 2 If the fuse fails again Disconnect all connections from the board with the exception of power CN1 Install a known good fuse if the fuse fails replace the chair circuit board If the fuse does not fail there is a short in the chair wiring Isolate the problem by plugging one connector at a time back into the board until the fuse fails again Repair or replace the chair wiring or components as needed 8 8 2011 Rev 0097 381 Page 26 Model 3900 Dental Chair 1 Disconnect the safety plate wiring harness from the chair circuit board at AN10 2 Using a test jumper P N 0014 287 short the two pins of AN10 on the circuit board a If the chair now functions normally with the exception of the safety plate function the safety plate wiring is faulty or one of the switches is faulty 3 Disconnect the safety plate wiring harness from the two switches in the chair lift arm using paper clips bent into a U shape short the wiring harness switch connections Chair is inoperative office has The safety plate wiring or power switches are faulty 4 Reconnect the wiring harness to AN10 on the circuit board a If the chair now functions normally one of the switches
25. your results the sum should equal 5K Ohm 20 3 If any of the results are not within specifications replace the potentiometer 8 8 2011 Rev 0097 381 Page 32 Model 3900 Dental Chair The position sensing BASE POSITION SENSOR potentiometer for that movement Ensure that the small gear is secure on the shaft of the Is not turning potentiometer and that the large gear is secure on the head of the lift arm shoulder bolt BACK POSITION SENSOR Ensure that the blue connecting tubing is secure on the shaft of the potentiometer and the helical drive shaft If the position sensing potentiometer drive is secure refer to Adjusting the position sensing potentiometers Base down is pressed back The back and base solenoid Switch the position of the solenoid connectors CN2 and CN3 on moves or back down is connectors are switched at their the chair circuit board pressed base moves connections on the chair circuit board The hydraulic system is low on 1 Remove the motor pump cover hydraulic fluid 2 Ch b eck the hydraulic fluid level with the chair base and back down You ll be able to see the fluid level through the side of the reservolr 3 Add fluid to the reservoir to about 1 inch from the top of the Chair pump is noisy for Base reservoir or Back Up functions Supply tubing from the reservoir Check all the hydraulic tubings and hoses making sure none are to the pump is kinked or pinched or kinke
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