SERVICE MANUAL for the MICROWAVE OVEN HOOD COMBINATION ( E Model Line) March, 1997 Printed in U.S.A.
THIS MANUAL CONTAINS INFORMATION NECESSARY FOR SERVICING THE KITCHENAID MICROWAVE OVEN HOOD COMBINATION , MODELS: KHMS105E KHMC107E THE MANUAL IS DESIGNED TO BE USED ONLY BY QUALIFIED SERVICE PERSONNEL. THE SERVICE INFORMATION IS ORGANIZED TO HELP YOU EASILY FIND WHAT YOU NEED. CHECK YOUR LOCAL BUILDING CODE FOR THE PROPER MODE OF INSTALLATION. IN THE ABSENCE OF LOCAL CODES, THIS UNIT SHOULD BE INSTALLED IN ACCORDANCE WITH THE NATIONAL ELECTRICAL CODE, ANSI/NFPA NO. 70 - 1990, OR LATEST EDITION, OR C22.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 TABLE OF CONTENTS Page iii Page Important Safety Information .............................................................................................................. v Theory Of Operation .........................................................................................................................1-1 Component Access .....................................................................................................
Page Component Description & Testing ..................................................................................................3-1 Important Safety Instructions .....................................................................................................3-1 The Thermal Fuses .....................................................................................................................3-4 The Blower Motor Capacitor ........................................................................
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page v IMPORTANT SAFETY INFORMATION This service manual is intended for factoryservice technicians only. We recommend that customers DO NOT service their own units, because of the complexity and risk of highvoltage electrical shock. WARNING Fire Hazard Do not obstruct the flow of ventilation air. The following information is used throughout this manual, and should be read carefully.
CAUTION WARNING TO SERVICE TECHNICIANS To avoid possible exposure to microwave radiation or energy, visually check the oven for damage to the door and door seal before operating the oven. Use your microwave survey meter to check the amount of leakage before servicing. In the event that the R.F. Ieakage exceeds 4 mw/cm 2 at 5 cm, appropriate repair must be made before continuing to service the unit. Check interlock function by operating the door latch.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page vii CAUTION KitchenAid microwave ovens have a monitoring system designed to assure proper operation of the safety interlock systems. WARNING The interlock monitor switch will immediately cause the oven fuse to blow if the door is opened while the following combined failure exists: DISCONNECT FROM POWER SUPPLY BEFORE SERVICING. CAUTION: HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE.
R.F. LEAKAGE TEST When checking for R.F. Ieakage, use an approved R.F. measuring device to assure less than 4 mw/cm 2 emission at 5 cm distance with a maximum scan rate of 2.5 cm/second, in compliance with U.S. Government Department of Health, Education and Welfare 21 CFR1030, performance Standard for Microwave Ovens. CAUTION EQUIPMENT • Electromagnetic energy leakage monitor (NARDA 8100B, HOLADAY H1501). • 600 ml glass beaker.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 1-1 THEORY OF OPERATION The microwave oven is powered by the 120volt line. Whenever the door is closed and a cooking function is programmed through the control panel’s keypad, relay contacts on the control board close, and complete a circuit from the L1 side to the neutral side of the line. Relay 4 controls the speed of the blower motor through the control panel.
The normally-closed (N.C.) contacts of relay 4 provide a potential circuit for the Base Thermal Fuse (see the following strip circuit). If the base of the oven exceeds 133˚F, the thermal fuse contacts close, and a circuit for the low-speed side of the blower motor is completed, which turns the motor on. The low-speed blower will operate until the base temperature drops below 104˚F and opens the thermal fuse contacts, and turns off.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-1 COMPONENT ACCESS COMPONENT SECTIONS • The Operating Control System Oven Light Socket Control Circuit Board Temperature Probe Socket Fan Motor Power Cord Blower Motor Capacitor Convection Heating Element Gas Sensor Synchronous Motor Cooktop Light Socket This section instructs you on how to service the individual components in the Microwave Oven Hood Combination.
GENERAL REMOVING THE MICROWAVE OVEN & CABINET WARNING 5. Support the front of the microwave oven and remove the two bolts and washers from the top of the oven. 6. Using two people, remove the microwave oven from its mounting location and set it on a protected (padded) work surface. 7. To remove the cabinet from the microwave oven, remove the two inside screws from the top of the cabinet that secure the vent grille to the oven.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-3 POWER CORD CABINET SCREW VENT GRILLE SCREWS (2) VENT GRILLE POWER CORD COVER CABINET SCREWS CABINET BASE PLATE WIRES RED WHITE (2) RED (2) WHITE COOKTOP LIGHT ASSEMBLY WIRING Removing The Cabinet 2-3 BASE PLATE SCREWS (6)
THE PROTECTION CONTROL SYSTEM REMOVING THE OVEN DOOR WARNING 1. Disconnect the electrical supply to the microwave oven. 2. Remove the vent grille and the base plate from the microwave oven (see the illustration on page 2-3). 3. Remove the six oven door hinge screws and remove the door. 4. Install the new oven door and then reassemble the microwave oven. Personal Injury Hazard Disconnect from the electrical supply before servicing the unit.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-5 REMOVING THE DOOR CHOKE 1. Disconnect the electrical supply to the microwave oven. 2. Open the oven door. Personal Injury Hazard 3. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Pry out the choke (gasket) along the edges of the door with a putty knife and remove the choke. 4.
REMOVING THE CONTROL PANEL WARNING 2. Remove the two screws from the top of the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). 3. Remove the screw from the top center tab of the control panel. 4. From the top and back of the control panel, lift the top locking tab and pull the top of the panel out slightly, then lift the bottom tabs of the panel out of the slots and pull it forward. Turn the panel over out of the way.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-7 REMOVING THE LINE FUSE 2. Remove the two screws from the top of the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). Personal Injury Hazard 3. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Remove the control panel from the microwave oven (see page 2-6). 4.
REMOVING/ADJUSTING THE INTERLOCK SWITCHES WARNING 5. Remove the center screw from the fan cover and fold the cover back so you can access the switches (see the illustration below). 6. Remove the two mounting screws from the interlock switch assembly, and position the assembly so you can easily access the switches and wiring. 7.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-9 INSET 2 1. PUSH THIS LOCKING ARM BACK TO UNLOCK SWITCH. INSET 1 1. RAISE THIS LOCKING ARM TO RELEASE SWITCH FROM HOUSING. SECONDARY INTERLOCK SWITCH ALL OTHER SWITCHES 2. PRESS BODY IN THIS DIRECTION TO REMOVE SWITCH FROM HOUSING. 2. ROTATE SWITCH ON THIS PIN AND REMOVE SWITCH FROM HOUSING. NOTE: THESE POSTS HOLD THE SWITCH IN PLACE ON THE HOUSING AND ARE STATIONARY.
MAKING ADJUSTMENTS 1. If necessary, adjust the interlock switch housing so that the switches operate properly. NOTE: The Interlock Monitor Switch provides an added safety check on the Primary and Secondary Interlock Switches. If the Primary and Secondary Interlock Switches allow the oven to operate with the door open, the Interlock Monitor Switch will blow the line fuse. 2. Close and secure the fan cover with its mounting screw. 3. Mount the control panel to the oven with the screw you removed earlier.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-11 REMOVING THE BASE THERMAL FUSE 2. Remove the two screws from the top of the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). Personal Injury Hazard 3. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Remove the control panel from the microwave oven (see page 2-6 for the procedure). 4.
REMOVING THE MAGNETRON THERMAL FUSE WARNING the grille (see the illustration on page 2-3). 3. Remove the control panel from the microwave oven (see page 2-6). Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. 4. Remove the center screw from the fan cover and fold the cover back so you can access the magnetron thermal fuse. Discharge the high voltage capacitor before working inside the oven.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-13 REMOVING THE CAVITY THERMAL FUSE 1. Disconnect the electrical supply to the microwave oven. 2. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Remove the microwave oven from its mounting location (refer to page 2-2 for the procedure). 3. Discharge the high voltage capacitor before working inside the oven.
REMOVING THE CONVECTION THERMISTOR WARNING 5. Remove the screws from the circulation pulley cover and the bracket, then remove the cover and the attached brackets from the top of the oven. Do not remove the brackets from the cover. 6. Remove the screw from the convection thermistor and remove the thermistor. 7. Cut the two white wires (not the thermistor wires) coming from the control board next to the splice. 8. Splice the white wires onto the ends of the new convection thermistor wires.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-15 BRACKETS CIRCULATION PULLEY COVER WHITE WIRES SENSOR COVER PHILLIPS SCREW CAUTION: WHEN REPLACING THE THERMISTOR, DO NOT CUT AND SPLICE THE WHITE WIRES, OR AN IMPROPER SIGNAL WILL BE SENT FROM THE THERMISTOR TO THE MICROCOMPUTER BOARD CONVECTION THERMISTOR 2-15
THE OPERATING CONTROL SYSTEM REMOVING THE OVEN LIGHT SOCKET WARNING the grille (see page 2-3 for the illustration). 3. Remove the mounting screw from the light cover and remove the cover. 4. Remove the bulb from the oven light socket. 5. Unplug the wire connectors from the oven light socket terminals and remove the socket mounting screw and light socket from the microwave oven. 6. Mount the new oven light socket and then reassemble the microwave oven.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-17 REMOVING THE CONTROL CIRCUIT BOARD 5. WARNING a) b) c) d) e) Personal Injury Hazard Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. 1. Disconnect the electrical supply to the microwave oven. 2. Remove the two screws from the top of the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). 3.
REMOVING THE TEMPERATURE PROBE SOCKET WARNING 4. From the top and back of the control panel, lift the top locking tab and pull the top of the panel out slightly, then lift the bottom tabs of the panel out of the slots and pull it forward. Set the panel inside the oven cavity while you work. 5. Remove the center screw from the fan cover and fold the cover back (unhook the three tabs) so you can access the temperature probe socket.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-19 REMOVING THE FAN MOTOR WARNING 2. Remove the microwave oven from its mounting location. 3. Remove the vent grille and the cabinet from the microwave oven (refer to page 2-2 for the procedure). 4. Unplug the wire connectors going to the line fuse. 5. Disconnect the wires from the terminals of the base thermal fuse. 6. Remove the five screws from the right side panel and remove the panel. 7.
REMOVING THE POWER CORD FAN MOTOR CONNECTOR WARNING (3) TOP RIGHT SIDE PANEL SCREWS Personal Injury Hazard Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. GROUND SCREW CAUTION: Because of the weight and size of the microwave oven, two people are required to safely move and install it. Failure to do so could result in personal injury. 1. Disconnect the electrical supply to the microwave oven. 2.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-21 REMOVING THE BLOWER MOTOR CAPACITOR 2. Remove the microwave oven from its mounting location (refer to page 2-2 for the procedure). Personal Injury Hazard 3. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Remove the vent grille and the cabinet from the microwave oven (refer to page 2-2 for the procedure). 4.
REMOVING THE CONVECTION HEATING ELEMENT WARNING 6. Remove the screw from the gas sensor and position the sensor out of the way. 7. Unhook the drive belt from the circulation fan pulleys and set it aside. 8. Remove the phillips screw from the convection thermistor that is located on the top plate. Remove the thermistor and position it out of the way. 9. Disconnect the wires from the convection heating element terminals.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-23 UNCLIP ELEMENT HERE HEATING ELEMENT MOUNTING SCREWS HEATING ELEMENT VIEWED FROM UNDER TOP PLATE BRACKETS CIRCULATION PULLEY COVER TOP PLATE MOUNTING SCREWS CONVECTION THERMISTOR GAS SENSOR TOP PLATE SENSOR COVER CONVECTION HEATING ELEMENT 2-23 YELLOW WIRES
REMOVING THE GAS SENSOR 3. Remove the vent grille and the cabinet from the microwave oven (refer to page 2-2 for the procedure). Personal Injury Hazard 4. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Unclip the gas sensor cover and remove it. 5. Discharge the high voltage capacitor before working inside the oven. Failure to do so could result in death or electrical shock.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-25 REMOVING THE SYNCHRONOUS MOTOR 3. Open the oven door and pry up the bottom panel and remove it from the oven (see inset 1). Personal Injury Hazard 4. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Lift the turntable off the motor shaft and remove it. 5. From the bottom of the oven, pull the connectors off the synchronous motor terminals. 6.
REMOVING A COOKTOP LIGHT SOCKET 2. Remove the base plate from the microwave oven (refer to page 2-2 for the procedure). Personal Injury Hazard 3. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Pull the connectors off the cooktop light socket terminals and set the base plate aside. 4. Bend the light socket holder tab down, and then twist the socket clockwise to remove it from the holder. 5.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-27 THE HIGH VOLTAGE COMPONENTS The components for service in this section include the: WARNING Magnetron High Voltage Rectifier High Voltage Capacitor High Voltage Transformer Personal Injury Hazard Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. The locations of the high voltage components are shown in the illustration below.
ACCESSING THE HIGH VOLTAGE COMPONENTS WARNING Personal Injury Hazard 3. Remove the vent grille, the cabinet, and base plate from the microwave oven (refer to page 2-2 for the procedure). 4. Remove the control panel from the microwave oven, unplug the wire connectors from the control board, and set the control panel aside (see page 2-17 for the procedure). 5. Unplug the blower motor cable from its connector and remove the motor from the oven. 6.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-29 REMOVING THE MAGNETRON 5. Remove the fan motor assembly from the unit (see the illustration on page 2-19 for the procedure). Personal Injury Hazard 6. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Unplug the wire connectors from the magnetron thermal fuse. 7. Remove the two screws from the magnetron thermal fuse and remove it. 8.
REMOVING THE HIGH VOLTAGE RECTIFIER AND THE HIGH VOLTAGE CAPACITOR WARNING Replacing The High Voltage Rectifier 1. Unplug one end of the high voltage rectifier from the high voltage capacitor terminal. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. 2. Remove the mounting screw from the capacitor strap flange at the other end of the high voltage rectifier, and remove the rectifier.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-31 HIGH VOLTAGE RECTIFIER MOUNTING FLANGE HIGH VOLTAGE CAPACITOR MOUNTING STRAP HV CAPACITOR SCREW TAB & SLOT WHITE WIRE INSULATED RED WIRE RED WIRE Removing The High Voltage Rectifier & Capacitor 2-31
REMOVING THE HIGH VOLTAGE TRANSFORMER 3. Discharge the high voltage capacitor. 4. Unplug the wire connector going to the line fuse. Personal Injury Hazard 5. Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock. Remove the fan motor assembly from the unit (see the illustration on page 2-19 for the procedure). 6. Unplug the five high-voltage transformer wire connectors. 7 Remove the four mounting screws from the transformer.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-1 COMPONENT DESCRIPTION & TESTING IMPORTANT SAFETY INSTRUCTIONS CAUTION Warning To Service Technicians! To avoid possible exposure to microwave radiation or energy, visually check the oven for damage to the door and door seal before operating any oven. Use a microwave survey meter to check the amount of leakage before servicing. In the event the R.F.
KitchenAid microwave ovens have a monitoring system designed to assure proper operation of the safety interlock systems. The interlock monitor switch will immediately cause the oven fuse to blow if the door is opened and the primary door interlock switch and/or the secondary interlock switch contacts fail in a closed position. CAUTION: REPLACE BLOWN FUSE WITH 15 AMPERE CLASS H FUSE ONLY.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 CAUTION Page 3-3 WARNING • High voltages are present during the cook cycle. Extreme caution should be observed at all times. • Disconnect the oven from electrical supply before servicing. Failure to do so could result in electrical shock or death. • Abrasive cleansers, steel-wool pads, gritty wash cloths, etc. can damage the control panel and the interior and exterior oven surfaces.
THE THERMAL FUSES There are three thermal fuses in the OTR Microwave Oven. They are: the magnetron thermal fuse, the cavity thermal fuse, and the base thermal fuse. The magnetron and cavity thermal fuses are located inside the highvoltage section of the oven. These two thermal fuses are normally-closed, and will open at a set temperature to disable the oven. Both of these fuses are resettable. The base thermal fuse is located directly behind the control panel.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-5 THE BLOWER MOTOR CAPACITOR The blower motor capacitor is located directly behind the control panel. It is in use any time the blower (vent) motor is operating. The ca- pacitor helps to maintain a constant voltage to the blower motor so that it runs more efficiently. LOCKING ARMS BLOWER MOTOR CAPACITOR RED WIRE YELLOW WIRE TESTING 1. Set the ohmmeter to the R x 10K scale. 2. Measure across the capacitor terminals.
THE GAS SENSOR depending upon the humidity of the oven. Changing humidity conditions, due to the cooking process within the oven cavity, causes a difference in potential between these two circuits. This difference is monitored by the microcomputer during cooking, allowing the microcomputer to determine the proper cook time. The gas sensor is used during the “Sensor Cook” operation of the oven. It is located above the oven and is mounted on the left side of the sensor cover.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-7 THE CONVECTION THERMISTOR thermistor signal going back to the microcomputer causes the heater relay to open and close, and cycles the heating element on and off. The convection thermistor is located under the circulation pulley cover and is used during the convection operation of the oven. When the temperature increases, the resistance of the thermistor decreases. The thermistor resistance is monitored by the microcomputer.
THE CONVECTION HEATING ELEMENT and the heater relay on the microcomputer board. During a convection, or combination cooking cycle, the heater cycles on and off to maintain the programmed cavity temperature. The heating element surrounds the convection fan blade and is not visible through the oven cavity. The 1400-watt convection heating element is located under the circulation pulley cover and the top plate. The heating element heats the air that is distributed into the oven cavity by the convection fan.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-9 MOTORS Blower Motor —Removes smoke and odors from the kitchen cooking area through outside venting or recirculation. Fan Motor —Cools the magnetron and circulates air through the oven during microwave cooking. Synchronous Motor —Distributes microwave energy into the oven during microwave cooking.
PROGRAMMING CHECKS TOUCH PANEL CONTINUITY TEST 1. Unplug the microwave oven’s power supply cord. 2. Open the oven door. 3. Plug the power cord back into the AC receptical.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-11 THINGS TO KNOW COMBINATION BAKE COMBINATION ROAST The combination bake temperature range is 150˚F to 450˚F. The combination bake time will be limited to a maximum of 199-minutes, 99-seconds. The combination roast temperature range is 150˚F to 450˚F. The combination roast time will be limited to a maximum of 199-minutes and 99-seconds.
CHARTS PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR CORRECTION Line fuse blows when power cord is plugged into a wall receptacle. Shorted wire in power cord, wiring harness, or overload circuit. 1. Oven will not operate. 1. No power at wall plug. 1. 2. Open wire in power cord or wiring harness. Control board. Line fuse. Thermal fuses. 2. 3. 4. 5. Check fuse or breaker box. Check wiring with ohmmeter for continuity. Check board. Check fuse. Check fuse. 3. 4. 5. 2.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-13 PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR CORRECTION Little or no heat is produced in the oven load. 1. High voltage transformer. 1. 2. Rectifier diode. 2. 3. High voltage capacitor. 3. 4. 5. Magnetron. Power selector. 4. 5. 1. Primary interlock switch. 1. 2. Shorted wire harness. 2. Oven lamp goes on with the door open, but the light goes out when the door is closed with the control on. 1.
PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR CORRECTION Blower motor will not operate. 1. 2. 3. Blower motor. Control board. Open or loose wiring in circuit to blower motor. 1. 2. 3. Check blower motor. Check control board. Use ohmmeter to check continuity, and repair wiring. Cooktop lamps do not come on. 1. 2. 3. 4. Bulb burned out. Control board. Lamp sockets. Open wiring between the above components. 1. 2. 3. 4. Check bulb. Check control board. Check lamp sockets.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-15 PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR CORRECTION Console will not display data, or has incorrect data. 1. No power at wall plug. 1. 2. 3. 4. 2. 3. 4. 5. Open line fuse. Thermal fuse. Thermal fuse on magnetron. Interlock safety switches. 6. Control board. 6. Check fuse or breaker box. Replace line fuse. Check thermal fuse. Check magnetron thermal fuse. Check interlock safety switches. Replace, if defective.
CHECKING FOR MICROWAVE ENERGY LEAKAGE CAUTION On every service call, checks for microwave energy emission must be made according to the following manner. 1. Remove the cooking rack from the oven cavity, if the microwave oven is so equipped. When checking for R.F. Ieakage, use an approved R.F. measuring device to assure less than 4 mw/cm 2 emission at 5 cm distance with a maximum scan rate of 2.5 cm/second, in compliance with U.S.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-17 MAKING THE MEASUREMENTS To measure for oven leakage: Measuring The Oven With The Cabinet Installed 1. Pour 275 (±25cc) of water into a 600 cc graduated beaker. 2. Place the beaker into the center of the microwave oven. 3. Set the energy leakage monitor to 2,450 MHz, and use it according to the manufacturer’s recommended test procedure to obtain the correct results. 4.
MEASURING MICROWAVE POWER OUTPUT USING THE IEC-705 RATING STANDARD When determining the microwave oven’s power output using the IEC-705 rating standard, the following conditions must be met: • When making microwave power output measurements, the oven is supplied with its rated line voltage, and operated at its maximum power output setting with a load of 1000 (±5) cc of potable water.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-19 COMPONENT TESTING WARNING FILAMENT WINDING ELECTRICAL SHOCK HAZARD HIGH VOLTAGE TRANSFORMER DISCONNECT THE POWER SUPPLY CORD FROM THE WALL OUTLET WHEN REMOVING THE CABINET FROM THE OVEN. PROCEED WITH THE TESTS ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR, AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER.
COMPONENT TEST PROCEDURE High-Voltage Capacitor Terminal-To-Terminal Set the ohmmeter to the R x 10 k scale, and measure the resistance across the capacitor terminals. RESULT a) Normal - The meter indicates several ohms, then gradually returns to infinity. b) Abnormal - The meter indicates infinity, or zero ohms (a short) immediately. CAPACITOR Blower Motor Capacitor Terminal-To-Case Set the ohmmeter to the R x 1 scale, and measure the resistance between each terminal and the case.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 COMPONENT TEST PROCEDURE Switches (with wire leads removed). All of the switches are measured in the same manner. N.O. and C Terminals Set the ohmmeter to the R x 1 scale, and measure the resistance between the normally-open (N.O.) and the common (C) terminals of the switch. N.C. CONTACTS C. Page 3-21 RESULT a) Normal - The meter indicates infinity. b) Abnormal - The meter indicates zero ohms (a short). N.O. CONTACTS N.C.
COMPONENT TEST PROCEDURE Convection Thermistor Set the ohmmeter to the R x 10 K scale. Remove the 6-pin connector from the circuit board and measure across terminals 5 & 6. a) Normal = 155 K to 350 K ohms @ 68˚F. b) Abnormal = Infinity, or zero ohms (a short). Convection Heating Element (with leads disconnected) Set the ohmmeter to the R x 1 scale, and measure across the terminals. a) Normal = 9 to 40 ohms @ 68˚F ±2˚. Gas Sensor Set the ohmmeter to the R x 1 scale.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-23 COMPONENT TEST PROCEDURE RESULT Touch Keyboard (see below). Measure the resistance between the terminal pins of the keypad (shown below) that you wish to check. For example: To measure the “TEMP PROBE” keypad, refer to the illustration, and: 1.Find the first terminal number along the top bar (pin 4). 2.Find the second terminal number in the side bar (pin 8). 3.Set the ohmmeter to the R x 1 scale.
COMPONENT TEST PROCEDURE Relay 2 Set the ohmmeter to the R x 1 scale, and check for continuity between the two relay terminal pins. Use the following steps. 1.Remove the wire connectors from the relay terminals. 2.Use a pair of alligator clips, and clip the ohmmeter leads to the two terminals of the relay. Make sure that you do not allow the clips to short to anything. 3.Plug the microwave oven into an AC receptical. 4.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-25 PRIMARY, MONITOR, & SECONDARY SWITCH CHECKOUT PROCEDURE NOTE: The following chart and strip circuits show the continuity and position of the door switches when the microwave oven door is open and closed. CONTINUITY TEST CHART SWITCH TESTING DOOR OPEN DOOR CLOSED Primary Interlock Disconnect the 4-pin connector from the control module. Check from the pink wire (pin 1) to the blue wire (pin 3).
— NOTES — 3-26
