Viking VHSO205SS Service Manual
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Viking VHSO205SS Service Manual

High speed convection microwave oven
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See also: Use and Care Manual , Installation Manual
In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specifi ed should
be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and
current, contact with following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor,
High Voltage Power Transformer, Magnetron, High Voltage Rectifi er Assembly, High Voltage Harness etc..)
BEFORE SERVICING ....................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL . ................................................................................................................ 3
MICROWAVE MEASUREMENT PROCEDURE . .................................................................................................... 4
FOREWORD AND WARNING ............................................................................................................................... 5
PRODUCT SPECIFICATIONS ............................................................................................................................... 6
GENERAL INFORMATION.................................................................................................................................... 6
OPERATION . .......................................................................................................................................................... 8
TROUBLESHOOTING GUIDE ............................................................................................................................. 15
TEST PROCEDURE ............................................................................................................................................ 17
TOUCH CONTROL PANEL .................................................................................................................................. 8
PRECAUTIONS FOR USING LEAD-FREE SOLDER . ......................................................................................... 3
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE................................................................. 33
PICTORIAL DIAGRAM ......................................................................................................................................... 41
POWER UNIT CIRCUIT ....................................................................................................................................... 4
CPU UNIT CIRCUIT . ............................................................................................................................................ 43
PARTS LIST ......................................................................................................................................................... 44
PACKING AND ACCESSORIES .......................................................................................................................... 49
This document has been published to be used for after sales service only. The contents are subject to
change without notice.
VIKING
SERVICE MANUAL

TABLE OF CONTENTS

Range Corporation
111 Front St., Greenwood, MS 38930
Tel: (888) 845-4641
HIGH SPEED CONVECTION
MICROWAVE OVEN
MODEL
VHSO205SS
1
VHSO205SS
S17M273VHS205
Page

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  • Page 1: Table Of Contents

    VIKING VHSO205SS SERVICE MANUAL S17M273VHS205 HIGH SPEED CONVECTION MICROWAVE OVEN MODEL VHSO205SS In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specifi ed should be used. WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifi er Assembly, High Voltage Harness etc..)

  • Page 2: Precautions To Be Observed Before And During Service To Avoid Possible Exposure To Excessive Microwave Energy

    VHSO205SS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPO- SURE TO EXCESSIVE MICROWAVE ENERGY (a) Do not operate or allow the oven to be operated with the door open. (b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1) interlock operation, () proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse. (c) Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections. (d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave genera- tion and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner. (e) A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner.

  • Page 3: Warning To Service Personnel

    VHSO205SS WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of pro- ducing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. Read the Service Manual carefully and follow all instructions. Don't Touch ! Danger High Voltage Before Servicing When the testing is completed, 1. Disconnect the power supply cord, and then remove...

  • Page 4: Microwave Measurement Procedure

    VHSO205SS MICROWAVE MEASUREMENT PROCEDURE A. Requirements: 1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm at any point 5cm or more from the external surface of the oven. ) Safety interlock switches: Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm at any point 5cm or more from the external surface of the oven. B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows: 1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
  • Page 5 SERVICE MANUAL VIKING PRODUCT DESCRIPTION MICROWAVE OVEN VHSO205SS GENERAL INFORMATION FOREWORD This Manual has been prepared to provide VIKING Products. Service Personnel with Operation and Service Information for the VIKING OPERATION HIGH SPEED MICROWAVE OVEN, VHSO05SS. It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory TROUBLESHOOTING GUIDE customer service. AND TEST PROCEDURE Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard.

  • Page 6: General Information

    VHSO205SS SPECIFICATION ITEM DESCRIPTION Power Requirements 40 Volts 7.9 Amperes (Microwave) / 14. Amperes (Convection)/ 1.8 Amperes (Speed Cooking) 60 Hertz / Single phase, 3 wire grounded Power Output 1000 watts (IEC Test Procedure) Operating frequency of 450MHz Top Heater Power Output 1500 Watts Side Heater Power Output 100 Watts Case Dimensions Width 30" Height -7/8" Depth 5-11/16" Cooking Cavity Dimensions (1.1 Cubic Feet ) Width 16-1/8" Height 8-3/8" Depth 13-5/8" Control Complement Touch Control System Timer (0 - 99 min. 99 seconds) Microwave Power for Variable Cooking Repetition Rate; HIGH POWER .......... Full power throughout the cooking time 90 PERCENT .............. approx. 90% of Full Power 80 PERCENT .............. approx. 80% of Full Power 70 PERCENT .............. approx. 70% of Full Power 60 PERCENT .............. approx. 60% of Full Power 50 PERCENT ..............

  • Page 7: Extension Cord

    VHSO205SS Electrical Requirements Receptacle Box Cover 3 Pronged Plug The electrical requirements are a 40 volt 60 Hz, AC only, 15 amp. protected electrical (6-15P) supply. It is recommended that a separate circuit serving only this appliance be provided. 3 Pronged Receptacle The 40 volt circuit is absolutely necessary for optimum cooking performance. The oven (6-15R) is equipped with a 3-prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded. Extension Cord If it is necessary to use an extension cord, use only a 3-wire extension cord that has a 3-blade grounding plug and a 3-slot receptacle that will accept the plug on the high speed oven. The marked rating of the extension cord should be AC 40 volt, 15 amp. or more. Be careful not to drape the cord over the countertop or table where it can be pulled on by children OVEN DIAGRAM or tripped over accidentally. CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRONG FROM THIS PLUG. 1 Door handle To open the door, pull the handle down and forward. Never hold the door handle when moving the oven. 2 Oven door with see-through window 3 Safety door latches The oven will not operate unless the door is securely closed. 4 Door hinges...

  • Page 8: Operation

    VHSO205SS OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions dur- switch, door sensing switch, relay (RY1), the primary ing oven operation. interlock relay (RY) and the secondary interlock switch are activated with the following results. The circuits to OFF CONDITION the turntable motor, the cooling fan motor, and the high Closing the door activates the door sensing switch and voltage components are de-energized, the oven lamp secondary interlock switch. (In this condition, the monitor remains on, and the digital read-out displays the time switch contacts are opened.) still remaining in the cook cycle when the door was When oven is plugged in, 40 volts A.C. is supplied to the opened. control unit. (Figure O-1).
  • Page 9 VHSO205SS SPEED BAKE COOKING 1. The coil of shut-off relays (RY1, RY3 and RY5) are energized, the oven lamp, cooling fan motor, turntable Touch the BAKE pad and then enter cooking time. When the motor and convection motor are turned on. start pad is touched, following operations occur; . The coil of relay (RY4) is energized by the control unit. (Figure O-3) The damper is moved to the closed position, closing 1. The contacts of the relays RY1, RY3 and RY5 are closed, the damper switch contacts. The closing of the damper and the oven lamp, turntable motor, convection motor switch contacts sends a signal to the LSI on the control and fan motors are energized. unit de-energizing the relay (RY4) and opening the circuit NOTE : The rotate direction of the convection motor is to the damper motor.

  • Page 10: Schematic Diagram

    VHSO205SS (REHEAT, POPCORN, COOK, DEFROST) base and it is energized for three (3) seconds and off Microwave options of Automatic cooking will automatically for 9 seconds. Two () seconds after the thermistor compute the microwave power, cooking time or defrosting is energized, the voltage across the temperature time. And the oven will cook according to the special cook- measurement circuit is sampled by the LSI and twenty ing sequence. five (5) seconds after the thermistor is cut off the LSI turns on the convection fan for three (3) seconds. FIRE SENSING FEATURE (MICROWAVE MODE) 3. The above procedure is repeated. If the difference This model incorporates a sensing feature which will stop between the first voltage measured (in step 1) and the...
  • Page 11 VHSO205SS SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. . COOKING TIME PROGRAMMED. NOTE: " " indicates components with potential above 50V. 3. “START” PAD TOUCHED. FUSE TEMP. FUSE LV TRANSFORMER SIDE HEATER THERMAL CUT-OUT TOP HEATER FUSE THERMAL F10A CUT-OUT SOLID-STATE RELAY FUSE1 2.5A CONTROL UNIT SOLID-STATE RELAY N.O. COM. SECONDARY INTERLOCK SWITCH NOTES: 1.
  • Page 12 VHSO205SS SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. . GRILL PAD TOUCHED. 3. COOKING TIME PROGRAMMED. NOTE: " " indicates components with potential above 50V. 4. “START” PAD TOUCHED. FUSE TEMP. FUSE LV TRANSFORMER SIDE HEATER THERMAL CUT-OUT TOP HEATER FUSE THERMAL F10A CUT-OUT SOLID-STATE RELAY FUSE1 2.5A CONTROL UNIT SOLID-STATE RELAY N.O. COM. SECONDARY INTERLOCK...

  • Page 13: Description And Function Of Components

    VHSO205SS DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM The door is opened by pulling the door handle down and 3. If the door is opened, and the primary interlock relay forward, referring to the figure D-1. When the door handle is and secondary interlock switch contacts fail to open, the pulled down, the latch heads are moved upward. And then monitor fuse blows simultaneously with closing of the when the door handle is pulled forward, the latch heads monitor switch contacts. are released from the latch hooks right and left. Now, the CAUTION: BEFORE REPLACING A BLOWN MONITOR door will open. Monitor switch FUSE TEST THE DOOR SENSING SWITCH, Latch hook left Latch PRIMARY INTERLOCK RELAY, SECOND-...
  • Page 14 VHSO205SS ο ο will open at 30 F (150 C) causing the oven to shut down. selected temperature. When the convection time reaches 0, When the thermal cut-out has cooled, the thermal cut-out the heating elements are de-energized and the convection ο ο closes at 66 F (130 fan stops operating and the oven shuts off. TOP HEATING ELEMENT Flow of hot air: The top heating element is located at the top of the oven The rotation direction of the convection motor is controlled cavity. It is intended to heat air driven by the convection fan. by relay RY6. When the convection fan rotates clockwise, The heated air is kept in the oven and force-circulated and the hot air from the oven cavity left side wall blows stronger reheated by the top heating element. than one from the oven cavity top wall. ( This mode is called “Convection mode”.) When the convection fan rotates coun- SIDE HEATING ELEMENT terclockwise, the hot air from the oven cavity top wall blows The side heating element is located at the left side of the stronger than one from the oven cavity left side wall. (This oven cavity. It is intended to heat air driven by the convection mode is called “JET mode”.) fan. The heated air is kept in the oven and force-circulated and reheated by the top heating element.

  • Page 15: Troubleshooting Guide

    VHSO205SS operation is selected by the control unit. position). 1-4. The signal from damper switch is re-sensed in the Microwave Cooking: control unit and shut-off relay (RY4) is turned off. Damper is in the open position, because a portion of cool- 1-5. The 40 volts A.C. to the damper motor is removed ing air is channelled through the cavity to remove steam and the motor turns off. and vapors given off from the heating foods. It is then ex- . When oven is microwave cooking: hausted at the top of the oven cavity into a condensation Damper is in the open position. compartment. 3. When oven is convection cooking: Convection, Preheat, Speed Grill, Speed Roast, Speed 3-1. Damper motor is energized by touching the Bake, or all cooking modes which use the top / side convection, temperature and START pads.
  • Page 16 VHSO205SS (CONVECTION, SPEED BAKE/ CONDITION OFF CONDITION COOKING CONDITION (MICROWAVE) GRILL/ROAST) POSSIBLE CAUSE AND DEFECTIVE PARTS A MAGNETRON B POWER TRANSFORMER C H.V. RECTIFIER ASSEMBLY D HIGH VOLTAGE CAPACITOR E SECONDARY INTERLOCK SWITCH F PRIMARY INTERLOCK SYSTEM G MONITOR SWITCH H MONITOR FUSE J MAGNETRON TEMPERATURE FUSE K THERMAL CUT-OUT (TOP) M TOP HEATING ELEMENT O THERMISTOR P DAMPER MOTOR Q DAMPER SWITCH U TOUCH CONTROL PANEL...

  • Page 17: Test Procedure

    VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER MAGNETRON ASSEMBLY TEST 1. Disconnect the power supply cord. . Remove the outer case cabinet, referring to “OUTER CASE CABINET REMOVAL”. 3. Open the oven door and block it open. 4. Discharge the high voltage capacitor. 5. Remove the back plate from the oven, referring to “BACK PLATE REMOVAL”. 6. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than 1 ohm. 7. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground. This test should indicate an infinite resistance. If there is little or no resistance the magnetron is grounded and must be replaced. 8. Reconnect all leads removed from components during testing. 9. Reinstall the outer case (cabinet). 10. Reconnect the power supply cord after the outer case is installed. 11. Run the oven and check all functions. MICROWAVE OUTPUT POWER The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted). HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE OBSERVED. Power output of the magnetron can be measured by performing a water temperature rise test. This test should only be used if above tests do not indicate a faulty magnetron and there is no defect in the following components or wiring: silicon rectifier, high voltage capacitor and power transformer. This test will require a...
  • Page 18 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER overheating of the power transformer. Check for restricted air flow to the power transformer, especially the fan motor (power transformer side). 8. Reconnect all leads removed from components during testing. 9. Reinstall the outer case (cabinet) and the back plate. 10. Reconnect the power supply cord after the outer case and the back plate are installed. 11. Run the oven and check all functions. (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEAS- URE THE FILAMENT AND HIGH VOLTAGE.) HIGH VOLTAGE RECTIFIER TEST 1. Disconnect the power supply cord. . Remove the outer case cabinet, referring to “OUTER CASE CABINET REMOVAL”. 3. Open the oven door and block it open. 4. Discharge the high voltage capacitor. 5. Remove the back plate from the oven, referring to “BACK PLATE REMOVAL”. 6. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals and observe, reverse the leads to the rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions, the rectifier is probably defective and should be replaced. 7. Reconnect all leads removed from components during testing. 8. Reinstall the outer case (cabinet) and back plate.
  • Page 19 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER PRIMARY INTERLOCK SYSTEM TEST DOOR SENSING SWITCH 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the door closed. If improper operation is indicated, replace the door sensing switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the turntable motor and oven light will be activated by RY1. PRIMARY INTERLOCK RELAY (RY) 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor.
  • Page 20 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER RELAY, SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with "monitor fuse and monitor switch assembly", even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised of a 0 ampere fuse and switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. BLOWN FUSE F10A 1. Disconnect the power supply cord. . Remove the outer case cabinet, referring to “OUTER CASE CABINET REMOVAL”. 3. Open the oven door and block it open. 4. Discharge the high voltage capacitor. 5. Remove the back plate from the oven, referring to “BACK PLATE REMOVAL”. 6. If the monitor fuse is blown, there could be short or ground in high voltage rectifier, magnetron, power transformer, high voltage capacitor or high voltage wire. Check them and replace the defective parts or repair the wire harness. 7. Reconnect all leads removed from components during testing. 8. Reinstall the outer case (cabinet) and the back plate.
  • Page 21 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE THERMAL CUT-OUT. THERMAL CUT-OUT (SIDE HEATER) TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the ο ο temperature of the thermal cut-out reaches approximately 30 F(150 C). The thermal cut-out resets...
  • Page 22 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 4. Discharge the high voltage capacitor. 5. Remove the back plate from the oven, referring to “BACK PLATE REMOVAL”. 6. Disconnect connector-E from the control unit. Measure the resistance of the thermistor with an ohmmeter. Connect the ohmmeter leads to Pin No’s B-5 and B-6. Room Temperature Resistance ο ο ο ο F(0 C) - 86 F(30 Approx. 360 kΩ - 15 KΩ 7. If the meter does not indicate above resistance, replace the thermistor. 8. Reconnect all leads removed from components during testing. 9. Reinstall the outer case (cabinet). 10. Reconnect the power supply cord after the outer case is installed. 11. Run the oven and check all functions. DAMPER MOTOR TEST When the power cord is plugged into the wall receptacle and 40 volts A.C. is supplied to the damper motor, the motor operates until the damper is opened and the damper switch closes. Then the damper motor stops operation. If the damper motor does not operate, check for A.C. voltage with a voltmeter at the motor. 1. Disconnect the power supply cord.
  • Page 23 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CONVECTION MOTOR CAPACITOR TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect input leads and check for short or open between the terminals using an ohmmeter. Checking with a high ohm scale, if the capacitor is normal, the meter will indicate continuity for a short time and should indicate an open circuit once the capacitor is charged. If the above is not the case, check the capacitor with an ohmmeter to see if it is shorted between the terminals. If it is shorted, replace the capacitor. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet) and the back plate. 7. Reconnect the power supply cord after the outer case and the back plate are installed. 8. Run the oven and check all functions. CONVECTION MOTOR TEST 1. Disconnect the power supply cord. . Remove the outer case cabinet, referring to “OUTER CASE CABINET REMOVAL”. 3. Open the oven door and block it open.
  • Page 24 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER In this service manual, troubleshooting by unit replacement is described according to the symptoms indi- cated. Before testing, 1) Disconnect the power supply cord, and then remove outer case. ) Open the door and block it open. 3) Discharge high voltage capacitor. 4) Disconnect the leads to the primary of the power transformer. 5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape. 1. Key Unit Panel NOTE ; 1) Re-install the outer case (cabinet). ) Reconnect the power supply cord after the outer case is installed. 3) Run the oven and check all functions. The following symptoms indicate a defective Key Unit Panel. a) When touching the pads, a certain pad produces no signal at all. b) When touching a number pad, two figures or more are displayed. c) When touching the pads, sometimes a pad produces no signal. If the Key Unit Panel is defective. 1) Disconnect the power supply cord, and then remove outer case.
  • Page 25 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER RELAY TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the leads to the primary of the power transformer. 5. Ensure that these leads remain isolated from other components and oven chassis by using insulation tape. 6. After that procedure, re-connect the power supply cord. 7. Remove the outer case and check voltage between Pin Nos. 1 and 9 of the 5 pin connector (CN-D) on the control unit with an A.C. voltmeter. The meter should indicate 40 volts, if not check oven circuit. Shut-off, Cook and Heater Relays Test These relays are operated by D.C. voltage Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, speed grill, speed roast, speed bake, or convection cooking condition. . voltage indicated ....Defective relay. DC. voltage not indicated .....Check diode which is connected to the relay coil. If diode is good, control unit is defective. RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS RY1 Approx. 7.0V D.C.
  • Page 26 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER arrows. And touch the number pad 5. And then touch the start pad. (3) The oven is in Defrost cooking condition. (4) The oven will operate as follows. WEIGHT 1ST STAGE ND STAGE 3RD STAGE LEVEL TIME LEVEL TIME LEVEL TIME Steaks/Chops 0.5lbs 70% 17sec. 60% 30sec. 30% 45sec. (5) If improper operation is indicated, the control unit is probably defective and should be checked. PROCEDURES TO BE TAKEN WHEN THE FUSE 1 ON THE PRINTED WIRING BOARD (PWB) IS OPEN.
  • Page 27 VHSO205SS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER NOISE FILTER TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the leads to the primary of the power transformer. 5. Using an ohm-meter, check between the terminals as described in the following table: NOISE FILTER UNIT MONITOR FUSE NOISE SUPPRESSION COIL LINE CROSS CAPACITOR 0.uF/ AC 50V LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR 0.0033uF/ AC 15V 0.0033uF/ AC 15V MEASURING POINT INDICATION OF OHM-METER Between N and H Open Circuit Between terminal N and GRY Short Circuit Between terminal H and RED Short Circuit If incorrect readings are obtained, replace the noise filter.

  • Page 28: Touch Control Panel

    VHSO205SS TOUCH CONTROL PANEL DIAGRAM The touch control section consists of the following units as shown in the touch control panel circuit. (1) Backlight LED function () LED function. (3) KEY function...
  • Page 29 VHSO205SS...
  • Page 30 VHSO205SS...
  • Page 31 VHSO205SS TOUCH CONTROL PANEL SERVICING 1. Precautions for Handling Electronic Components 5) Re-connect the power supply cord after the outer case This unit uses CMOS LSI in the integral part of the circuits. is installed. When handling these parts, the following precautions should 6) Run the oven and check all functions. be strictly followed. CMOS LSI have extremely high imped- A. On some models, the power supply cord between the touch ance at its input and output terminals. For this reason, it is control panel and the oven itself is so short that the two can’t easily influenced by the surrounding high voltage power be separated. For those models, check and repair all the source, static electricity charge in clothes, etc. and sometimes controls (sensor-related ones included) of the touch control it is not fully protected by the built-in protection circuit. panel while keeping it connected to the oven. In order to protect CMOS LSI. B. On some models, the power supply cord between the touch 1) When storing and transporting, thoroughly wrap them in control panel and the oven proper is long enough that they aluminium foil. Also wrap all PW boards containing them in...

  • Page 32: Precautions For Using Lead-Free Solder

    VHSO205SS PRECAUTIONS FOR USING LEAD-FREE SOLDER 1. Employing lead-free solder “Main PWB” of this model employs lead-free solder. The LF symbol indicates lead-free solder, and is attached on the PWBs and service manuals. The alphabetical character following LF shows the type of lead-free solder. Example: Sn-Ag-Cu Indicates lead-free solder of tin, silver and copper. 2. Using lead-free wire solder When fixing the PWB soldered with the lead-free solder, apply lead-free wire solder. Repairing with conventional lead wire solder may cause damage or accident due to cracks. ο As the melting point of lead-free solder (Sn-Ag-Cu) is higher than the lead wire solder by 40 C, we recommend you to use a dedicated soldering bit. 3. Soldering ο As the melting point of lead-free solder (Sn-Ag-Cu) is about 0 C which is higher than the conventional lead solder ο by 40 C, and as it has poor solder wettability, you may be apt to keep the soldering bit in contact with the PWB for extended period of time. However, since the land may be peeled off or the maximum heat-resistance temperature of parts may be exceeded, remove the bit from the PWB as soon as you confirm the steady soldering condition. Lead-free solder contains more tin, and the end of the soldering bit may be easily corroded. Make sure to turn on and off the power of the bit as required. If a different type of solder stays on the tip of the soldering bit, it is alloyed with lead-free solder. Clean the bit after every use of it.

  • Page 33: Component Replacement And Adjustment Procedure

    VHSO205SS COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operat- ing the oven.

  • Page 34: Power Supply Cord Replacement

    VHSO205SS CAUTION 1. DISCONNECT T HE OVEN FROM T HE POWER SUPPLY BEFORE REMOVING THE OUTER CASE CABINET. . DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. Special screw NOTE Screw Driver When replacing the outer case cabinet, the two (2) (Type: TORX T0 H or special Torx screws must be reinstalled in the same GTXH0-100) locations.

  • Page 35: Magnetron Removal

    VHSO205SS mounting angle to the bottom plate from under the bottom 10. R emove the four (4) screws holding the power transformer plate. to the transformer mounting angle. 9. Remove the two () screws holding the transformer 11. N ow, the power transformer is free. mounting angle to the bottom plate from the top of the bottom plate. MAGNETRON REMOVAL 1. Disconnect the power supply cord. 10. R elease the main wire harness from the hole of the . Remove the outer case cabinet, referring to “OUTER magnetron separator and the hook of the fan motor.
  • Page 36 VHSO205SS SOLID-STATE RELAY (MAGNETRON SIDE) REMOVAL 1. Disconnect the power supply cord. magnetron separator. . Remove the outer case cabinet, referring to “OUTER 8. Remove the three (3) screws holding the magnetron CASE CABINET REMOVAL”. separator to the bottom plate and the thermal cover 3. Open the oven door and block it open. back. 4. Discharge the high voltage capacitor.

  • Page 37: Convection Motor Removal

    VHSO205SS mounting angle to the bottom plate from under the bottom cavity. plate. 3. N ow, the convection duct assembly is free. 30. R emove the thirteen (13) screws holding the convection 33. R emove the nine (9) screws holding the heater duct duct to the oven cavity and the heater duct upper. upper to the oven cavity. 31. R emove the convection duct assembly from the oven 34. R emove the heater duct upper from the oven cavity. 35. N ow, the heater duct upper assembly is free. SIDE HEATING ELEMENT REMOVAL DUCT UPPER ASSEMBLY AND CONVECTION DUCT 1. Disconnect the power supply cord.

  • Page 38: Door Replacement And Adjustment

    VHSO205SS 3. Open the oven door and block it open. 3. Reconnect the wire leads to the switch. 4. Discharge the high voltage capacitor. 4. Make sure that the monitor switch is operating properly 5. Disconnect the wire leads from the switch. and check continuity of the monitor circuit. Refer to 6. Remove the one (1) screw holding the latch hook (right chapter “Test Procedure” and “Adjustment procedure. or left) to the oven cavity front plate, and release the Monitor switch latch hook (right or left). Latch hook left Latch 7. Keep pushing the stopper tub holding the switch to the...

  • Page 39: Door Disassembly

    VHSO205SS 5. Close the door. . The door is positioned with its face pressed toward oven 6. Remove the two () door springs from the door cam right, cavity front plate. oven hinge right, door com left and oven hinge left. 3. Reinstall the outer case cabinet and check for microwave 7. Release the door cams right and left from the right and leakage around the door with an approved microwave left door cam pins of the door. survey meter. (Refer to Microwave Measurement 8. Remove the door cams right and left from the oven cavity Procedure.) NOTE: The door on a microwave oven is designed to act front plate. 9. Open the door assembly at an angle of more than 90½ as an electronic seal preventing the leakage of with the oven cavity front plate.

  • Page 40: Cpu Unit Circuit

    VHSO205SS CHOKE COVER handle levers. . P ull out the two () handle pins from the two () handle 8. Insert a putty knife (thickness of about 0.5 mm) into levers. the gap between the choke cover and the door panel 3. R emove the two () handle levers from the door panel. assembly as shown in Figure C-5. 4. N ow, the door panel is free. 9. Lift up the choke cover. 10. N ow, the choke cover is free from the door panel MIDDLE DOOR GLASS assembly.
  • Page 41 VHSO205SS...
  • Page 42 VHSO205SS RTRNPA002WRZZ 6.8 1W D1-D4 1N4002L x4 DTA143ES R5 300 Q5 KIA79L05P AC240V/60HZ H-12 G5SB-14 DC24V TURN OVER TURN OVER MOTOR DAMPER MOTOR MOTOR MOTOR G5NB-1A DC24V DTD143ES DAMPER MOTOR G5NB-1A DC24V (G-2) MOTOR H-11 DOOR(B) G5NB-1A DC24V (J1) H-10...
  • Page 43 VHSO205SS...

  • Page 44: Parts List

    VHSO205SS PARTS LIST Note: The parts marked "∆" may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY ELECTRICAL PARTS QSW-MA085WRE0 Secondary interlock/door sensing/damper switch RMOTDA191WRE0 Damper motor...
  • Page 45 VHSO205SS REF. NO. PART NO. DESCRIPTION Q'TY PCUSGA603WREZ Cushion PFPF-A225WRPZ Thermal insulation L PSKR-A377WRFZ Rear separator PFPF-A227WRPZ Thermal insulation Upper PFPF-A228WRPZ Thermal insulation Bottom PGLSPA579WRZZ Lamp glass PPACGA189WREZ Silcon packing PREFHA069WRPZ Thermal cover Upper PREFHA078WRWZ Thermal cover Left PREFHA071WRPZ Thermal cover D...
  • Page 46 VHSO205SS REF. NO. PART NO. DESCRIPTION Q'TY TCAUHB008MRR0 User caution label PZET-A011WRE0 Thermal insulator LHLDWA029WRE0 Cord holder LHLDWA013WRE0 Purse lock LL CFZK-B766MRK0 Anti-tip bracket TCAUSB015MRR0 Label FDUC-B080MRK0 Back duct TCAUAB060MRR0 NHW caution label TCAUHB014MRR0 French user caution label TCAUSB012MRR0 BIK-height caution label...
  • Page 47 VHSO205SS...
  • Page 48 VHSO205SS CONTROL PANEL PARTS 30-1 DOOR PARTS...

  • Page 49: Packing And Accessories

    VHSO205SS MISCELLANEOUS Actual wire harness may be different than illustration. 20-pin wire harness 128 Pursu lock L Main wire harness Main wire harness transformer Power unit 134 Pursu lock LL POSITION OF PURSE LOCK PACKING AND ACCESSORIES 118 LOW RACK...
  • Page 50 VHSO205SS NOTES:...
  • Page 51 VHSO205SS NOTES:...

  • Page 52: Range Corporation 111 Front St., Greenwood, Ms

    VHSO205SS COPYRIGHT © 2006 BY VIKING ALL RIGHTS RESERVED No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher. VIKING RANGE CORPORATION 111 Front St., Greenwood, MS 38930 Tel: (888) 845-4641...

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