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SAFETY FIRST

•  Don’t bypass the power cord’s ground lead with two-wire extension cords or plug adaptors.

•  Don’t disconnect green/yellow safety-earth ground wire that connects the ground lug of the power receptacle to

the chassis ground.

•  Don’t plug in the power cord until directed by the installation instructions.

•  Don’t repair the furnace unless you are a qualified technician and know how to work with hazardous voltages.

•  Don’t locate and operate the furnace in close proximity to combustible materials. 

•  Observe all WARNING statements. They point out situations that can cause injury or equipment damage.

•  Disconnect the power cord before attempting to service.

•  It is the user’s responsibility to use only cleaning agents and materials that will not result in hazards to the

equipment or material contained within.

•  When replacing the main power supply cord use only a direct equivalent high-temperature cable.

•  When replacing the main fuse use only a direct equivalent.

SAFETY

Summary of Contents for 3-130

Page 1: ...Vulcan Furnace Service Manual Models A 130 3 130 3 550PD A550 3 550 3 550A A 1750 3 1750 3 1750A CERAMCO...

Page 2: ...how to work with hazardous voltages Don t locate and operate the furnace in close proximity to combustible materials Observe all WARNING statements They point out situations that can cause injury or e...

Page 3: ...UIDES 5 1 5 3 1 Power Supply 5 1 5 3 2 Microprocessor 5 1 5 3 3 Peripheral Drive 5 1 5 3 4 Motor Drive 5 1 5 3 5 Analog Circuitry 5 1 5 3 6 Display Board 5 1 5 3 7 Fan Drive Control 5 2 5 4 TROUBLESHO...

Page 4: ...the set value of RP2 As Vpin3 is near in value of Vref a proportional control takes over i e power is delivered by bursts to the load To slow down the heatup time of the muffle RP2 set clockwise and...

Page 5: ...iac gate output pulse current is about 60mA The triac is triggered in quadrants II and III Synchronization is provided by resistor R10 Its value determines the trigger pulse length 2 3 3 TRIAC DRIVE A...

Page 6: ...ed voltage across their terminals NOTES ________________________________________________ ________________________________________________ ________________________________________________ _____________...

Page 7: ...CONTROL 2 5 BLOCK DIAGRAM Power Supply D1 C1 R11 120 240V 60 50Hz Line Return Cabinet 6 8V 8 6V Set Point Pot Rate Control Pot Amplifier U1 Comparator Power Supply Triac Driver U2 Thermocouple Power...

Page 8: ...2 6 SCHEMATIC 2 4 SECTION 2 TROUBLESHOOTING A CONTROL...

Page 9: ...SECTION 2 TROUBLESHOOTING A CONTROL 2 7 CONTROL CIRCUIT BOARD Rate Control Temperature Meter Connection Triac Gate Muffle Connections Setpoint Potentiometer Thermocouple Amplifier Proportional Control...

Page 10: ...N RED YELL GATE BLK WHT GRN YELL GRN YELL CABINET GND 230V A 1750 230V HOOK UP HEATING PLATE RIAC HEATSINK TRIAC RED P1 P1 P5 AC1 AC2 MT1 MT2 TAN P6 C C D A A A B B B D DOOR SAFETY SWITCH THERMOCOUPLE...

Page 11: ...rcuit board is performed in one single step 3 4 1 REQUIRED TEST EQUIPMENT Multimeter Pot adjustment tool WARNING With control drawer opened dangerous voltage points may be exposed Contact with any of...

Page 12: ...is connected to an opto isolator U7 The isolator s output is connected to the gate of the muffle triac The muffle triac may be activated anytime during an AC cycle but once activated it can only be op...

Page 13: ...is given to help isolate the problem for a particular failure mode 5 3 TROUBLESHOOTING GUIDES 5 3 1 POWER SUPPLY To determine a faulty power supply use the table on page 5 3 To troubleshoot a faulty...

Page 14: ...ifier is defective If the output voltage stays at maximum positive typically 1 3 of the supply voltage the input voltage should be more postitive than the input voltage 5 4 3 TRIAC The gate to power l...

Page 15: ...ve Tmax 20 C This could mean The Tmax was set up too low for this program The destination temperature is relatively low compared to the programmed heat rate eg too much temperature overshoot ERR 8 EEP...

Page 16: ...power down Muffle does not heat after power up Not in start cycle Door switch not closed No door movement after switch is pressed Furnace is in TEST mode Motor connector J5 loose POWER SUPPLY VOLTAGE...

Page 17: ...1 ohm DC to U11 2 15 30V Not shorted or open PT1 to PT4 Not shorted or open MICROPROCESSOR Fault Setup Check Results desired Nonfunctional N A U9 3 2 4 9MHz sinusoid operation X1 approximately 0 4V U...

Page 18: ...ay OK Turn furnace D2 D3 D4 D6 Not shorted or open Off MOTOR DRIVE CIRCUIT Fault Setup Check Results desired No door up or down Furnace in idle U8 16 12 VDC when switch is activated Disconnect J5 U8 1...

Page 19: ...increase typical Turn furnace off Reconnect No Err2 at elevated TC wires temperatures DISPLAY BOARD Fault Setup Check Results desired LCD dots are all Furnace in idle J8 1 5V on or off at power up J4...

Page 20: ...264V 60 50Hz Peripheral Drive 12V U2 U1 U4 D1 RT1 U1 U2 K1 K2 Muffle Relays Triac driver Sonar U8 M U6 U9 Pg 5 9 Pg 5 9 Pg 5 9 Pg 5 9 Pg 5 11 Pg 5 11 Pg 5 10 Thermocouple Multiplexed A D Cold Jct Ref...

Page 21: ...5 9 5 8 SCHEMATICS SECTION 5 TROUBLESHOOTING 3 STAGE POWER SUPPLY...

Page 22: ...5 10 SECTION 5 TROUBLESHOOTING 3 STAGE 5 8 SCHEMATICS TEMPERATURE CIRCUIT LCD DISPLAY CIRCUIT...

Page 23: ...5 11A 5 8 SCHEMATICS SECTION 5 TROUBLESHOOTING 3 STAGE MICROPROCESSOR CIRCUIT...

Page 24: ...5 11B 5 8 SCHEMATICS SECTION 5 TROUBLESHOOTING 3 STAGE...

Page 25: ...5 12 SECTION 5 TROUBLESHOOTING 3 STAGE PD A 5 9 WIRING DIAGRAM...

Page 26: ...up mode shows 1000 C The new setup temperature Tcal is now found by the following calculation 500 C 520 C Tcal 961 x1000 961 C Note Abort the cycle before turning off the furnace This is the new Tcal...

Page 27: ...s used in the furnaces 7 1 SECTION 7 SERVICE PARTS A CONTROL 3 STAGE HEATING PLATE ASSY New 9493426 130 230V 9493364 550 100 120V 9493470 550 9493392 1750 MUFFLE INSULATION 9493341 130 9493361 550 Fac...

Page 28: ...ludes muffle insulation and 2 heating plates 230V 9493778 550 PD 100 120V 9493779 550 PD 9493996 550A Factory Repair 1750A HEATING PLATE ASSY 230V 9493364 550 PD 100 120V 9493470 550PD MUFFLE INSULATI...

Page 29: ...FUSE 16 Amp 120V 9320137 FUSE 12 Amp 120V 9494462 ADAPTER PLATE 120V 9493534 REAR PANEL 3 550PD FURNACE CABINET ASSY 9493320 130 FURNACES 9493354 550 FURNACES 9493384 1750 FURNACES 9493807 3 550 PD FU...

Page 30: ...86 3 550A 3 1750A FAN DUCT ASSY 9493970 3 550A 3 1750A DOOR SPRING 9493368 130 9493908 550 9492754 1750 2 PL SCREW 10 32 x 50 KEP 4 PL HANDLE 9390246 DOOR 9493321 130 9493350 550 9493380 1750 DOOR INS...

Page 31: ...120V A 550 R9493450 200 240V A 550 R9493451 200 240V A 1750 FUSE 20A S N 9525 and 9320072 earlier SCREW 6 32 x 375 RELAY 1750 ONLY 9320075 TRIAC 9303015 HEATSINK PYROMETER 9390451 KNOB SET POINT 9355...

Page 32: ...100 125V R9493447 200 240V Replaced by R9495232 Not Shown TERMINAL BLOCK 9390487 DISPLAY PCB R9493347 TC WIRES SCREW 6 32 x 375 SCREW 6 32 x 1 75 FUSE 1A 9320071 TRIAC 9303015 HEATSINK MEMBRANE SWITCH...

Page 33: ...D NUT 1 4 20 HEX PIVOT ARM SCREW 10 32 SEM BRACE 9493363 BRACKET MOTOR LINKAGE 9493532 BOLT SHOULDER 375 SCREW 8 32 SEM BRACKET MOTOR 9493362 SCREW 8 X 375 SCREW 8 X 50 BRACKET SPRING SPRING 9356016 M...

Page 34: ...e needed 8 2 TRIAC TOOLS Phillips 2 screwdriver 1 4 nut driver needle nose pliers 8 2 1 Follow steps 8 1 1 through 8 1 2 of CONTROL DRAWER REMOVAL 8 2 2 Disconnect wires from triac located at the rear...

Page 35: ...ribbon cable at control PCB 8 3 3 Peel off membrane switch Use knife if needed 8 3 4 Clean front panel surface with isopropyl alcohol Allow to dry thoroughly 8 3 5 Place the new membrane switch by loc...

Page 36: ...nents 8 4 1 Follow steps 8 1 1 through 8 1 2 of CONTROL DRAWER REMOVAL 8 4 2 Disconnect grey ribbon connector 8 4 3 Remove from snap on standoffs 8 4 4 Replace with new Display PCB 8 4 5 Connect grey...

Page 37: ...1 through 8 1 2 of CONTROL DRAWER REMOVAL 8 5 2 Disconnect wires AC1 AC2 MT1 MT2 and 4 muffle wires from power board 8 5 3 Disconnect orange wire from triac 8 5 4 Disconnect wires from pyrometer 8 5 5...

Page 38: ...s 8 6 1 Follow steps 8 1 1 through 8 1 2 of CONTROL DRAWER REMOVAL 8 6 2 Disconnect wires from power switch 8 6 3 Disconnect ribbon connectors 8 6 4 Remove relay and door switch wires 8 6 5 Disconnect...

Page 39: ...components Figure 1 Disconnect wires from Power Switch Figure 4 Remove Door Switch Wires Figure 7 Remove 4 Screws from PCB Figure 10 Insert PCB in standoff tighten 4 Screws Figure 2 Disconnect Ribbon...

Page 40: ...the 2 screws on each side of door 8 7 3 Rotate door out from cabinet and tighten 4 screws Check to make sure that rope contacts muffle lip when closed and insulation clears cabinet when lifted 8 7 4 I...

Page 41: ...fle holes Cut tie wraps located on terminals insulation Slide the piece of insulating sleeve provided over the existing ones and tie wrap at 1 below the heat shield It may take a few attempts to locat...

Page 42: ...5 Remove two screws one each side 8 9 6 Pull pry out muffle assy with attached front panel from wraparound 8 9 7 Remove screw used to secure thermocouple and pull thermocouple from muffle 8 9 8 Remov...

Page 43: ...details 8 10 3 Disconnect thermocouple from pyrometer 8 10 4 Remove nut Replace thermocouple by reversing previous steps and replace nut 8 11 THERMOCOUPLE 3 STAGE CONTROL TOOLS bladed screwdriver phi...

Page 44: ...e furnace 8 12 4 Disconnect muffle wires Refer to wiring diagram 5 9 8 12 5 Disconnect thermocouple from circuit board 8 12 6 Pull pry out muffle assy with attached front panel from wraparound 8 12 7...

Page 45: ...50 PD 8 ohms 8 ohms 24 ohms 8 13 THERMOCOUPLE 3 550 PD TOOLS bladed screwdriver phillips head screwdriver 1 4 nutdriver WARNING Disconnect power from the wall outlet before attempting to service the f...

Page 46: ...t 8 13 5 Replace with new thermocouple by reversing previous steps 8 11 1 thru 8 11 4 8 14 POWER SWITCH TOOLS Slotted screwdriver 8 14 1 Follow steps 8 1 1 through 8 1 2 of CONTROL DRAWER REMOVAL 8 14...

Page 47: ...which support rear panel 8 15 4 Remove the 2 screws to free motor linkage bracket from base 8 15 5 Disconnect wires Female quick connect terminals from motor 8 15 6 Remove 4 screws to free motor 8 15...

Page 48: ...e original packaging Equipment damaged in shipment as a result of improper packing may not be paid by the carrier DENTSPLY will not be responsible for damages resulting from improper packing Ship prep...

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