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A product of VULCAN-HART

LOUISVILLE, KY 40201-0696

Form 24694 (April 2001)

- NOTICE -

This Manual is prepared for the use of trained Vulcan Service
Technicians and should not be used by those not properly
qualified. If you have attended a Vulcan Service School for this
product, you may be qualified to perform all the procedures
described in this manual.

This manual is not intended to be all encompassing. If you have
not attended a Vulcan Service School for this product, you should
read, in its entirety,  the repair procedure you wish to perform  to
determine if you have the necessary tools, instruments and skills
required to perform the procedure. Procedures for which you do
not have the necessary tools, instruments  and skills should be
performed by a trained Vulcan Service Technician.

Reproduction or other use of this Manual, without the express
written consent of Vulcan-Hart, is prohibited

.  

                            

SERVICE MANUAL

MODEL VFBMW

ELECTRIC

FLASHBAKE

®

 / MICROWAVE

OVEN

ML 126807

Summary of Contents for VFBMW

Page 1: ... be all encompassing If you have not attended a Vulcan Service School for this product you should read in its entirety the repair procedure you wish to perform to determine if you have the necessary tools instruments and skills required to perform the procedure Procedures for which you do not have the necessary tools instruments and skills should be performed by a trained Vulcan Service Technician...

Page 2: ... 12 Control Panel 12 Control Board 13 Keypad Assembly 14 Display 14 LED Display 14 Relay Board 14 Door Switch Assembly 15 Upper Lamp Housing and Duct Assembly 16 Upper Lamp Assembly 18 Upper Lamp Fan 19 Upper Lamp Housing Ducts 19 Right Duct 19 Left Duct 20 Cavity Thermistor 20 High Voltage Transformer 20 Magnetron 21 Magnetron Cooling Fan 22 Lower Lamp Housing and Duct Assembly 23 Lower Lamp Fan ...

Page 3: ...gen Lamps 32 Radiation Leakage Test 32 ELECTRICAL OPERATION 33 Component Function 33 Component Location 34 TCO Locations Switch Locations 35 Control Board Layout 36 Control Board Connector Identification 36 Air Flow Diagrams 37 Combi Cook 37 Magnetron 38 Microwave 38 Component Wiring Diagrams 39 Thermal Cut Outs 39 Door Switches 40 Halogen Lamps 41 Schematic Diagram 42 Wiring Diagram 44 Sequence o...

Page 4: ...his manual before the oven is released to the owner 5 A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner GENERAL INTRODUCTION General The combination FlashBake and microwave oven cooks the outside of foods much like conventional radiant heat while also penetrating the surface so the inside cooks simult...

Page 5: ...evels greater than 7 all power levels lamps and microwave will be reduced by the control board to 7 for the remainder of the combi cook cycle The consumer will not notice any change in display readout however they may notice that the halogen lamps are cycling differently than expected In the unlikely event that internal oven cavity temperature exceeds 600 F combi cook operation will be terminated ...

Page 6: ... the control board which controls the upper halogen lamps U the lower halogen lamp L as well as the high voltage magnetron circuits M operates on a duty cycle of 32 seconds This means the power level you select for each component controls the percentage of on time during each 32 second period of time Example Upper halogen lamp pair set at 80 U 08 lower halogen lamp set at 50 L 05 and microwave set...

Page 7: ...agnetron area NOTE New type connectors are used on this oven Some have locking tabs that must be released by pressing in the appropriate place before connectors can be separated When installing connectors take extra care to ensure all tabs in gang connectors are properly aligned before connecting When installing connectors listen for click sound and stop If connector is seated on too far it may be...

Page 8: ...screws securing back panel 4 Pull bottom of back panel away from unit to disengage it from bottom panel 5 Reverse procedure to install Bottom panel WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove screws securing bottom panel 2 Disengage bottom panel from back panel and remove bottom pane...

Page 9: ...erse procedure to install VENT FAN CAPACITOR WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove MAIN COVER 2 Disconnect wires from capacitor 3 Remove screw securing capacitor 4 Reverse procedure to install VENT FAN WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT B...

Page 10: ...ecuring assembly to top of magnetron NOTE Screws removed from magnetron are different 6 Disconnect motor connector and thermal fuse connector 7 Undo wire wrap and work wires out 8 Remove screw securing lamp socket NOTE Lamp and socket are replaced as one piece 9 If door is to be removed first remove motor and then remove screw securing bottom of door 10 Reverse procedure to install DAMPER HOUSING ...

Page 11: ... following components and replace the ones found to be malfunctioning A Door primary interlock switch B Door secondary interlock switch C Door monitor switch NOTE During reassembly before installing main cover and after all necessary components are replaced and adjusted a radiation leak test MUST be performed in the magnetron area WARNING DUE TO HIGH VOLTAGE SPECIAL CARE SHOULD BE TAKEN WHEN MEASU...

Page 12: ...ke cover B The latch can be removed by pushing it against spring tension to the end of its travel Then pry latch out of mounting holes and lift it up enough to be able to disconnect the spring C Remove door handle by removing screws securing it 4 Reverse procedure to install 5 Perform RADIATION LEAKAGE TEST CONTROL PANEL ASSEMBLY WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN C...

Page 13: ...ward 6 Disconnect eight plugs from control board CAUTION When reassembling be certain all plugs are correctly mated If plug is colored connect it to same color connector on board Failure to connect correctly will result in damage to unit 7 Lift panel and work pivot arms out of holes and remove panel from unit Control Board 1 Remove CONTROL PANEL 2 Disconnect connectors going to display board LED b...

Page 14: ...ng display board and remove board 3 Reverse procedure to install LED Display 1 Remove CONTROL BOARD 2 Remove DISPLAY 3 Remove two screws securing LED display assembly and remove assembly 4 Reverse procedure to install RELAY BOARD WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove MAIN COVER...

Page 15: ...E A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove CONTROL PANEL 2 Identify and disconnect connectors from the three switches 3 Remove two screws securing assembly to unit 4 Carefully slide assembly up to disengage tabs and rotate assembly out of unit 5 Remove a switch by pressing appropriate tab to release switch CAUTION Flex tabs only enough to release switch Excessive ...

Page 16: ...MBLY Parts that can be accessed when upper lamp housing and duct assembly is removed Cavity thermistor Thermal cut out located at top of magnetron Magnetron Upper lamp assembly Upper lamp fan assembly Damper door assembly Magnetron fan assembly Lower lamp fan assembly High voltage transformer WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT ...

Page 17: ... fuse C Disconnect wires from high voltage capacitor D Work high voltage capacitor wires out of wire retainer on duct E Pass connector and wires down through hole 8 For Model FBMW3 A Disconnect wires from vent fan motor capacitor B Remove NOISE FILTER BOARD C Disconnect wires from high voltage capacitor D Work high voltage capacitor wires out of wire retainer on duct E Pass connector and wires dow...

Page 18: ...E ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove UPPER LAMP HOUSING AND DUCT ASSEMBLY 2 Remove lamp housing by straightening two tabs on each side and then separating it from the duct assembly 3 Work lamp wires out of wire retainers and disconnect wires from thermal cut outs CAUTION Use clean dry cloth to han...

Page 19: ...P HOUSING AND DUCT ASSEMBLY 2 Work wires out of wire retainer 3 Remove three screws and lift assembly out 4 Reverse procedure to install UPPER LAMP HOUSING DUCTS WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED Right Duct 1 Remove UPPER LAMP HOUSING AND DUCT ASSEMBLY 2 Remove two screws from under...

Page 20: ...ERMISTOR WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove UPPER LAMP HOUSING AND DUCT ASSEMBLY 2 Remove two screws securing mounting bracket NOTE Wires may be inside cable wrap 3 Disconnect thermistor plug from control board 4 Reverse procedure to install HIGH VOLTAGE TRANSFORMER WARNING ...

Page 21: ...ling main cover and after all necessary components are replaced and adjusted a radiation leak test MUST be performed WARNING DUE TO HIGH VOLTAGE SPECIAL CARE SHOULD BE TAKEN WHEN MEASURING AROUND THE MAGNETRON 1 Remove UPPER LAMP HOUSING AND DUCT ASSEMBLY 2 Remove MAGNETRON COOLING FAN 3 Remove two screws securing side panel to base and let it hang off to the side 4 Disconnect lead wires from magn...

Page 22: ... in place and completely seated to prevent leakage MAGNETRON COOLING FAN WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove UPPER LAMP HOUSING AND DUCT ASSEMBLY 2 Remove two screws securing fan housing to side panel 3 Disconnect motor connector 4 Disconnect connector for lower lamp fan moto...

Page 23: ... lamp life will be shortened Clean cold lamps with a cloth moistened with alcohol cleaner to remove skin oil or other residue 1 Remove BOTTOM PANEL 2 Disconnect lamp wiring connector 3 Remove four screws securing assembly to machine 4 Carefully work out from under turntable motor 5 Disconnect wires from thermal disk 6 Reverse procedure to install LOWER LAMP FAN WARNING DISCONNECT THE ELECTRICAL PO...

Page 24: ...ut with assembly or fall out when assembly is removed 5 During reassembly washer must be installed to prevent microwave energy leakage 6 Installation is easier if motor plate and ceramic shaft are assembled and then placed on oven 7 Reverse procedure to install THERMAL CUT OUTS Cavity Top Left NOTE This thermal cut out is nonresetable When replacing be sure to determine cause of failure WARNING DI...

Page 25: ...he oven cavity under the duct must be kept clean for proper air circulation Upper Lamps WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED FRONT DISK 1 Remove MAIN COVER 2 Disconnect wires from disk 3 Bend tabs up enough to slide disk out 4 Reverse procedure to install REAR DISK 1 Remove VENT FAN 2 ...

Page 26: ...k 5 Reverse procedure to install CAPACITOR High Voltage WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED NOTE During reassembly before installing main cover and after all necessary components are replaced and adjusted a radiation leak test MUST be performed in the magnetron area WARNING DUE TO HIG...

Page 27: ...h an insulated handled screwdriver or insulated jumper wire 4 Remove screw securing wire lead from diode to the chassis 5 Remove diode from capacitor 6 Reverse procedure to install LOW VOLTAGE TRANSFORMER WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove CONTROL PANEL 2 Remove screw securi...

Page 28: ...G ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED 1 Remove MAIN COVER 2 Remove screw securing inlet cover grill and lift grill out 3 Remove screw securing ground wire NOTE This screw has machine threads 4 Using a small flat bladed screwdriver press in on locking tab and lift up front edge of assembly and unhook back tab from base plate 5 Disconnect connectors from board 6 Reverse proce...

Page 29: ...UTION Check the ground do not operate the oven on an extension cord This oven is designed to be used when grounded CAUTION Avoid inserting nails wire etc through any holes in the oven during operation CAUTION Personnel should not be exposed to the microwave energy DOOR LATCHING ADJUSTMENT WARNING DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX PLACE A TAG ON THE CIRCUIT BOX ...

Page 30: ...9 5 Mega ohm once the capacitor is charged 5 A shorted capacitor will show continuous continuity 6 An open capacitor will show a constant 9 5Mega ohm due to the internal 9 5Mega ohm resistor 7 Resistance between each terminal and chassis should be infinite Diode If the diode is suspected substitute a known good diode and operate oven Low Voltage Transformer WARNING DISCONNECT THE ELECTRICAL POWER ...

Page 31: ...move MAIN COVER 2 Remove CONTROL PANEL ASSEMBLY 3 Discharge high voltage capacitor by shorting the terminals of the high voltage capacitor with an insulated handled screwdriver or insulated jumper wire 4 Check 20 Amp Fuse for continuity and proper size NOTE Do not use any other fuse or size except 20 Amp 5 Remove monitor switch leads to isolate switch A Check continuity of switch with door open an...

Page 32: ...sed to customer and after any repair NOTE During reassembly before installing outer panel and after all necessary components are replaced and adjusted a radiation leak test MUST be performed prior to installing the outer cover NOTE Leakage must be less than 2 mW cm2 milliwatts per centimeter squared for a fully assembled oven NOTE Leakage must be less than 5 mW cm2 for an oven with the outer cover...

Page 33: ...SPLAY Displays information needed by the customer to operate the oven THERMISTOR Signals the control board the temperature in the cavity The control board then keeps the fans running as needed at the end of a cook cycle up to approximately 1 minute Also provides information to adjust cooking parameters based on oven temperature Can turn oven off if temperature reaches between 600 F and 700 F DIODE...

Page 34: ...tors door position signals control board which controls direction and operation of the damper door motor If switch shorts or opens the damper door will continually cycle open and closed until one complete switch cycle is detected THERMAL FUSE Monitors temperature in damper housing HALOGEN LAMPS Supplies visible and infrared light used to cook the product MAGNETRON Provides microwave energy to cook...

Page 35: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 35 of 52 TCO Locations Switch Locations ...

Page 36: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 36 of 52 CONTROL BOARD LAYOUT Control Board Connector Identification ...

Page 37: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 37 of 52 AIR FLOW DIAGRAMS Combi Cook ...

Page 38: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 38 of 52 Magnetron Microwave ...

Page 39: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 39 of 52 COMPONENT WIRING DIAGRAMS Thermal Cut Outs ...

Page 40: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 40 of 52 Door Switches ...

Page 41: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 41 of 52 Halogen Lamps ...

Page 42: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 42 of 52 SCHEMATIC DIAGRAM ...

Page 43: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 43 of 52 ...

Page 44: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 44 of 52 WIRING DIAGRAM ...

Page 45: ...FLASHBAKE MICROWAVE OVEN ELECTRICAL OPERATION Form 24694 April 2001 Page 45 of 52 ...

Page 46: ... by control board depending on signals received from thermistor and cooking controls 1 Lamps and magnetron are energized a Relays RY20 and RY21 for lower lamps and relays RY19 and RY22 for upper front lamp energize and lamps start Approximately 2 seconds later relays RY18 and RY23 energize and upper rear lamp starts b Relay RY2 energizes and powers magnetron c Lamps and magnetron cycle on 32 secon...

Page 47: ...ord head use your volt ohm meter and check resistance from L1 to Neutral The resistance should be approximately 22 ohms Note that this reading is shown in the schematic diagram at the low voltage transformer primary resistance 3 If you do not read continuity from L1 to Neutral suspect the following open fuse open cavity thermal cut out TCO low voltage transformer open primary winding open magnetro...

Page 48: ...ty temperature detected during microwave oven cooking SYMPTOM POSSIBLE CAUSES Oven does not operate No clock display oven cavity lamp or keypad responses 1 Power cord 2 Main circuit breaker open 3 20 Amp fuse open 4 Open cavity thermal cut out 5 Open low voltage transformer winding 6 Open magnetron thermal cut out 7 Open thermal fuse 8 Control board malfunction 9 Associated wiring and wiring conne...

Page 49: ... halogen lamp covers need cleaned to remove build up of grease and food spatterings 7 Check upper and lower halogen lamp operation 8 Perform microwave performance test 9 Restricted air flow Improper air flow can cause the halogen lamps or magnetron tube to cycle on the thermal cut outs Food items appear to be over cooked or burned 1 Incorrect type of cooking selected microwave vs combi cook 2 Inco...

Page 50: ...FLASHBAKE MICROWAVE OVEN TROUBLESHOOTING Form 24694 April 2001 Page 50 of 52 TROUBLESHOOTING FLOW CHART ...

Page 51: ...17 Cavity thermistor 854065 18 Magnetron fan assembly 854065 19 Magnetron assembly 854065 20 Thermal cutout cavity 854065 21 Transformer high voltage 854065 23 Lower lamp thermal cutout 854065 26 Switch micro interlock monitor 854065 27 Switch micro primary door 854065 34 Vent motor capacitor 854065 39 LED assembly 854065 42 Upper blower assembly 854065 43 Lower blower assembly 854065 44 Fuse 8540...

Page 52: ...FLASHBAKE MICROWAVE OVEN F24694 April 2001 Printed in U S A NOTES ...

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