. SERVICE MANUAL for the MICROWAVE OVEN HOOD COMBINATION ( E Model Line) March, 1997 Printed in U.S.A. THIS MANUAL CONTAINS INFORMATION NECES- SARY FOR SERVICING THE KITCHENAID MICRO- WAVE 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 EAS- ILY FIND WHAT YOU NEED. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page iii TABLE OF CONTENTS Page Important Safety Information.v Theory Of Operation.1-1 Component Access.2-1 Component Sections.2-1 General. 2-2 Removing The Microwave Oven & Cabinet.2-2 The Protection Control System. Control Circuit Board Checklist.3-24 Primary, Monitor, & Secondary Switch Checkout Procedure.3-25 Tech Tips.4-1 Wiring Diagrams.4-1 Strip Circuits.4-3 Specifications.4-7 Specification Charts.4-8 Model & Serial Number Explanation.4-12 KitchenAid Microwave Hood Warranty.
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KITCHENAID ASSUMES NO RESPONSIBILITY FOR ANY REPAIRS MADE ON OUR PRODUCTS B Y A N Y O N E O T H E R T H A N A U T H O R I Z E D. CAUTION WARNING TO SERVICE TECHNICIANS To avoid possible exposure to microwave ra-. Proper operation of the microwave ovens diation or energy, visually check the oven for requires that the magnetron be properly damage to the door and door seal before assembled to the waveguide and cavity. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page vii CAUTION KitchenAid microwave ovens have a monitor- WARNING ing system designed to assure proper opera- tion of the safety interlock systems. The interlock monitor switch will immediately.
LEAKAGE TEST When checking for R.F. Ieakage, use an ap- CAUTION proved R.F. Measuring device to assure less than 4 mw/cm emission at 5 cm distance with a maximum scan rate of 2.5 cm/second, in EQUIPMENT compliance with U.S. Government Department.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 1-1 THEORY OF OPERATION The microwave oven is powered by the 120- Relay 4 controls the speed of the blower motor volt line. Whenever the door is closed and a 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. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-1 COMPONENT ACCESS COMPONENT SECTIONS. The Operating Control System This section instructs you on how to service the individual components in the Microwave Oven Light Socket Oven Hood Combination. These components Control Circuit Board (shown below) and their sections are as fol- Temperature Probe Socket. GENERAL REMOVING THE MICROWAVE OVEN & CABINET Support the front of the microwave oven WARNING and remove the two bolts and washers from the top of the oven. Personal Injury Hazard Disconnect from the electrical supply be- fore servicing the unit.
Failure to do so could result in death or electrical shock. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-3 POWER CORD VENT CABINET GRILLE SCREW SCREWS (2) VENT GRILLE POWER CORD COVER CABINET SCREWS CABINET BASE PLATE WIRES BASE PLATE (2) WHITE SCREWS (2) RED WHITE COOKTOP LIGHT ASSEMBLY WIRING Removing The Cabinet. THE PROTECTION CONTROL SYSTEM REMOVING THE OVEN DOOR Disconnect the electrical supply to the WARNING microwave oven. Remove the vent grille and the base plate Personal Injury Hazard from the microwave oven (see the illus- tration on page 2-3). Disconnect from the electrical supply be- fore servicing the unit. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-5 REMOVING THE DOOR CHOKE Disconnect the electrical supply to the WARNING microwave oven. Open the oven door.
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Personal Injury Hazard Pry out the choke (gasket) along the edges Disconnect from the electrical supply be- of the door with a putty knife and remove fore servicing the unit. REMOVING THE CONTROL PANEL Remove the two screws from the top of WARNING the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). Personal Injury Hazard Remove the screw from the top center tab Disconnect from the electrical supply be- of the control panel. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-7 REMOVING THE LINE FUSE Remove the two screws from the top of the WARNING cabinet for the vent grille and remove the grille (see the illustration on page 2-3). Personal Injury Hazard Remove the control panel from the micro- wave oven (see page 2-6). REMOVING/ADJUSTING THE INTERLOCK SWITCHES Remove the center screw from the fan WARNING cover and fold the cover back so you can access the switches (see the illustration below). Personal Injury Hazard Remove the two mounting screws from Disconnect from the electrical supply be- the interlock switch assembly, and posi- fore servicing the unit.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-9 INSET 2 1. PUSH THIS LOCKING INSET 1 ARM BACK TO UNLOCK SWITCH.
RAISE THIS LOCKING ARM TO RELEASE SWITCH FROM HOUSING. ALL OTHER PRESS BODY IN SECONDARY SWITCHES THIS DIRECTION TO. MAKING ADJUSTMENTS LATCH HOUSING If necessary, adjust the interlock switch housing so that the switches operate prop- erly. NOTE: The Interlock Monitor Switch provides an added safety check on the Primary and Secondary Interlock Switches.
DOOR If the Primary and Secondary Interlock LATCH Switches allow the oven to operate with the door open, the Interlock Monitor Switch. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-11 REMOVING THE BASE THERMAL FUSE Remove the two screws from the top of WARNING the cabinet for the vent grille and remove the grille (see the illustration on page 2-3). Remove the control panel from the micro- Personal Injury Hazard wave oven (see page 2-6 for the proce. REMOVING THE MAGNETRON THERMAL FUSE the grille (see the illustration on page WARNING 2-3). Remove the control panel from the micro- Personal Injury Hazard wave oven (see page 2-6).
Disconnect from the electrical supply be- Remove the center screw from the fan fore servicing the unit. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-13 REMOVING THE CAVITY THERMAL FUSE Disconnect the electrical supply to the WARNING microwave oven. Remove the microwave oven from its Personal Injury Hazard mounting location (refer to page 2-2 for the procedure). REMOVING THE CONVECTION THERMISTOR Remove the screws from the circulation WARNING pulley cover and the bracket, then re- move the cover and the attached brack- ets from the top of the oven. Do not re- Personal Injury Hazard move the brackets from the cover. Disconnect from the electrical supply be- Remove the screw from the convection fore servicing the unit. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-15 BRACKETS CIRCULATION PULLEY COVER WHITE WIRES PHILLIPS CAUTION: WHEN REPLACING THE SCREW THERMISTOR, DO NOT CUT AND SPLICE SENSOR THE WHITE WIRES, OR AN IMPROPER COVER SIGNAL WILL BE SENT FROM THE THERMISTOR TO THE MICROCOMPUTER BOARD CONVECTION THERMISTOR.
THE OPERATING CONTROL SYSTEM REMOVING THE OVEN LIGHT SOCKET the grille (see page 2-3 for the illustra- WARNING tion). Remove the mounting screw from the light cover and remove the cover. Personal Injury Hazard Remove the bulb from the oven light Disconnect from the electrical supply be- socket.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-17 REMOVING THE CONTROL CIRCUIT BOARD Unplug the following connectors from the WARNING control circuit board: a) 3-wire connector at CN4. Personal Injury Hazard b) 2-wire connector at CN2. C) 2 connectors on relay RY2.
REMOVING THE TEMPERATURE PROBE SOCKET From the top and back of the control WARNING 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 Personal Injury Hazard slots and pull it forward. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-19 REMOVING THE FAN MOTOR Remove the microwave oven from its WARNING mounting location.
Remove the vent grille and the cabinet from the microwave oven (refer to page Personal Injury Hazard 2-2 for the procedure). REMOVING THE POWER CORD WARNING FAN MOTOR TOP RIGHT CONNECTOR SIDE PANEL SCREWS PLASTIC Personal Injury Hazard COVER Disconnect from the electrical supply be- fore servicing the unit. Failure to do so could result in death or electrical shock. GROUND SCREW LINE FUSE. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-21 REMOVING THE BLOWER MOTOR CAPACITOR Remove the microwave oven from its WARNING mounting location (refer to page 2-2 for the procedure). Personal Injury Hazard Remove the vent grille and the cabinet from the microwave oven (refer to page Disconnect from the electrical supply be- 2-2 for the procedure). REMOVING THE CONVECTION HEATING ELEMENT Remove the screw from the gas sensor WARNING and position the sensor out of the way.
Unhook the drive belt from the circulation fan pulleys and set it aside. Personal Injury Hazard Remove the phillips screw from the con- Disconnect from the electrical supply be- vection thermistor that is located on the fore servicing the unit. 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 CONVECTION MOUNTING SCREWS THERMISTOR GAS SENSOR TOP PLATE SENSOR COVER YELLOW. REMOVING THE GAS SENSOR Remove the vent grille and the cabinet WARNING from the microwave oven (refer to page 2-2 for the procedure). Personal Injury Hazard Unclip the gas sensor cover and remove Disconnect from the electrical supply be- fore servicing the unit. Failure to do so Remove the screw from the top center tab 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 Open the oven door and pry up the bottom WARNING panel and remove it from the oven (see inset 1).
Lift the turntable off the motor shaft and Personal Injury Hazard remove it. REMOVING A COOKTOP LIGHT SOCKET Remove the base plate from the micro- WARNING wave oven (refer to page 2-2 for the pro- cedure). Personal Injury Hazard Pull the connectors off the cooktop light socket terminals and set the base plate Disconnect from the electrical supply be- aside. 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 WARNING include the: Magnetron Personal Injury Hazard High Voltage Rectifier High Voltage Capacitor Disconnect from the electrical supply be- High Voltage Transformer fore servicing the unit.
ACCESSING THE HIGH VOLTAGE COMPONENTS Remove the vent grille, the cabinet, and WARNING base plate from the microwave oven (re- fer to page 2-2 for the procedure). Remove the control panel from the micro- Personal Injury Hazard wave oven, unplug the wire connectors Disconnect from the electrical supply be- from the control board, and set the control fore servicing the unit.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-29 REMOVING THE MAGNETRON Remove the fan motor assembly from the WARNING unit (see the illustration on page 2-19 for the procedure). Personal Injury Hazard Unplug the wire connectors from the mag- netron thermal fuse. REMOVING THE HIGH VOLTAGE RECTIFIER AND THE HIGH VOLTAGE CAPACITOR Replacing The High Voltage Rectifier WARNING Unplug one end of the high voltage recti- fier from the high voltage capacitor termi- Personal Injury Hazard nal.
Disconnect from the electrical supply be- Remove the mounting screw from the fore servicing the unit. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-31 HIGH VOLTAGE RECTIFIER MOUNTING FLANGE HIGH VOLTAGE CAPACITOR MOUNTING STRAP TAB & CAPACITOR SLOT SCREW WHITE WIRE INSULATED RED WIRE RED WIRE Removing The High Voltage Rectifier & Capacitor 2-31. REMOVING THE HIGH VOLTAGE TRANSFORMER Discharge the high voltage capacitor. WARNING Unplug the wire connector going to the line fuse.
Personal Injury Hazard Remove the fan motor assembly from the Disconnect from the electrical supply be- unit (see the illustration on page 2-19 for fore servicing the unit. 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. 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. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-3 CAUTION WARNING.
High voltages are present during the cook. Disconnect the oven from electrical supply be- cycle. Extreme caution should be observed fore servicing. Failure to do so could result in at all times. THE THERMAL FUSES There are three thermal fuses in the OTR The base thermal fuse is located directly be- Microwave Oven.
They are: the magnetron hind the control panel. It is a normally-open thermal fuse, the cavity thermal fuse, and the fuse that, when closed, activates the blower base thermal fuse. 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 pacitor helps to maintain a constant voltage to behind the control panel. It is in use any time the blower motor so that it runs more effi- the blower (vent) motor is operating. THE GAS SENSOR depending upon the humidity of the oven. The gas sensor is used during the “Sensor Changing humidity conditions, due to the cook- Cook” operation of the oven. It is located ing process within the oven cavity, causes a above the oven and is mounted on the left side difference in potential between these two cir- of the sensor cover.
Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-7 THE CONVECTION THERMISTOR The convection thermistor is located under thermistor signal going back to the microcom- the circulation pulley cover and is used during puter causes the heater relay to open and the convection operation of the oven. THE CONVECTION HEATING ELEMENT The 1400-watt convection heating element is and the heater relay on the microcomputer located under the circulation pulley cover and board. During a convection, or combination the top plate. The heating element heats the cooking cycle, the heater cycles on and off to air that is distributed into the oven cavity by maintain the programmed cavity temperature. 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.
PROGRAMMING CHECKS TOUCH PANEL CONTINUITY TEST If the sensor is defective, or if the wires are not properly connected, you will see the following Unplug the microwave oven’s power sup- display: ply cord. Open the oven door. – f 1 – 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 The combination roast temperature range is 150˚F to 450˚F. The combination bake time 150˚F to 450˚F. The combination roast time will be limited to a maximum of 199-minutes, will be limited to a maximum of 199-minutes 99-seconds. CHARTS TEST PROCEDURE PROBLEM POSSIBLE CAUSE OR CORRECTION Shorted wire in power cord, Check wiring with ohm- Line fuse blows when power wiring harness, or overload meter for continuity.
Cord is plugged into a wall circuit. Use separate 15- to 20- ampere circuit. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-13 TEST PROCEDURE POSSIBLE CAUSE PROBLEM OR CORRECTION High voltage transformer. Check the high voltage Little or no heat is produced transformer. In the oven load.
Check the high voltage Rectifier diode. TEST PROCEDURE PROBLEM POSSIBLE CAUSE OR CORRECTION Blower motor. Check blower motor. Blower motor will not oper- ate. Control board. Check control board.
Open or loose wiring in Use ohmmeter to check circuit to blower motor. Continuity, and repair wiring.
Bulb burned out. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-15 TEST PROCEDURE POSSIBLE CAUSE PROBLEM OR CORRECTION No power at wall plug. Check fuse or breaker Console will not display data, box. Or has incorrect data. Open line fuse. Replace line fuse. CHECKING FOR MICROWAVE ENERGY LEAKAGE CAUTION When checking for R.F.
Ieakage, use an ap- proved R.F. Measuring device to assure less than 4 mw/cm emission at 5 cm distance with On every service call, checks for microwave a maximum scan rate of 2.5 cm/second, in energy emission must be made according to 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 Pour 275 (±25cc) of water into a 600 cc graduated beaker. Cabinet Installed Place the beaker into the center of the MEASUREMENT NOTES: microwave oven. MEASURING MICROWAVE. The time (in seconds) for the temperature of the water to rise by a value of 10˚C ±2˚ is POWER OUTPUT USING THE measured.
The initial and final water tem- IEC-705 RATING STANDARD peratures are selected so that the maximum difference between the final water tempera- When determining the microwave oven’s power ture, and the ambient temperature, is 5˚C. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-19 COMPONENT TESTING WARNING FILAMENT WINDING ELECTRICAL SHOCK HAZARD HIGH VOLTAGE DISCONNECT THE POWER SUPPLY CORD TRANSFORMER FROM THE WALL OUTLET WHEN REMOVING THE CABINET FROM THE OVEN. PROCEED WITH THE TESTS ONLY AFTER DISCHARG- ING THE HIGH VOLTAGE CAPACITOR, AND REMOVING THE WIRE LEADS FROM THE.
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COMPONENT TEST PROCEDURE RESULT High-Voltage Capacitor Terminal-To-Terminal a) Normal - The meter indi- cates several ohms, then Set the ohmmeter to the R x 10 k gradually returns to in- scale, and measure the resistance finity. Across the capacitor terminals. B) Abnormal - The meter indicates infinity, or zero CAPACITOR. Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 3-21 COMPONENT TEST PROCEDURE RESULT Switches (with wire leads re- N.O. And C Terminals moved).
All of the switches are a) Normal - The meter indi- Set the ohmmeter to the R x 1 measured in the same manner. COMPONENT TEST PROCEDURE RESULT a) Normal = 155 K to 350 K Set the ohmmeter to the R x 10 K Convection Thermistor ohms @ 68˚F.
B) Abnormal = Infinity, or Remove the 6-pin connector from zero ohms (a short). The circuit board and measure across terminals 5 &. 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 Normal Readings: the terminal pins of the keypad KEYPAD NOT PRESSED - In- (shown below) that you wish to dicates more than 1 MΩ. COMPONENT TEST PROCEDURE RESULT Relay 2 Set the ohmmeter to the R x 1 scale, and check for continuity WARNING: When you apply between the two relay terminal power to the unit, be careful pins. Use the following steps.
Not to touch any of the high 1.Remove the wire connectors voltage circuits. 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 DOOR DOOR.
— NOTES — 3-26.