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SERVICE MANUAL
for the
MICROWAVE OVEN
HOOD COMBINATION
( E Model Line)
March, 1997
Printed in U.S.A. LIT4317216
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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. CHECK YOUR LOCAL BUILDING CODE FOR THE PROPER MODE OF INSTALLATION. IN THE AB- SENCE OF LOCAL CODES, THIS UNIT SHOULD BE INSTALLED IN ACCORDANCE WITH THE NATIONAL ELECTRICAL CODE, ANSI/NFPA NO. 70 - 1990, OR LATEST
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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 ..............................................................................................
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Page Component Description & Testing ..................................................................................................3-1 Important Safety Instructions.....................................................................................................3-1 The Thermal Fuses .....................................................................................................................3-4 The Blower Motor Capacitor .............................................................
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Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page v IMPORTANT SAFETY INFORMATION This service manual is intended for factory- service technicians only. We recommend that WARNING customers DO NOT service their own units, because of the complexity and risk of high- Fire Hazard voltage electrical shock. Do not obstruct the flow of ventilation air. The following information is used throughout this manual, and should be read carefully. Electrical Shock Hazard It
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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. operating the oven. Use your microwave sur- Never operate the magnetron unless it is vey meter to check the amount of leakage properly installed. before servicing. In the event that the
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Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page vii CAUTION KitchenAid microwave ovens have a monitor- ing system designed to assure proper opera- tion of the safety interlock systems. WARNING The interlock monitor switch will immediately DISCONNECT FROM POWER SUPPLY cause the oven fuse to blow if the door is BEFORE SERVICING. opened while the following combined failure exists: CAUTION: HIGH VOLTAGES ARE Primary door interlock switch and/or second- PRESENT DURING THE C
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R.F. LEAKAGE TEST When checking for R.F. Ieakage, use an ap- proved R.F. measuring device to assure less 2 CAUTION 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 • Electromagnetic energy leakage monitor of Health, Education and Welfare 21 CFR1030, (NARDA 8100B, HOLADAY H1501). performance Standard for Microwave Ovens. • 600 ml glass beaker. A properly operating door and seal assembly will normally register
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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 base thermal cooking function is programmed through the fuse will also turn the blower motor on to its control panel’s keypad, relay contacts on the low speed if the temperature reaches 133˚F. control board close, and complete a circuit
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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. N L1 MICROCOMPUTER BOARD 15A LINE LOW-VOLTAGE FUSE TRANSFORMER
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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 lows: Fan Motor Power Cord • General Blower Motor Capacitor Cabinet Convection Heating Element • The Protection Cont
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GENERAL REMOVING THE MICROWAVE OVEN & CABINET 5. Support the front of the microwave oven and remove the two bolts and washers WARNING 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. 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 elec
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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 RED (2) WHITE (2) RED WHITE SCREWS (6) COOKTOP LIGHT ASSEMBLY WIRING Removing The Cabinet 2-3
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THE PROTECTION CONTROL SYSTEM REMOVING THE OVEN DOOR 1. Disconnect the electrical supply to the microwave oven. WARNING 2. 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. Failure to do so 3. Remove the six oven door hinge screws could result in death or electrical shock. and remove the door. 4. Install the new oven door and then reas- CAUTION: Because
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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. WARNING 2. Open the oven door. Personal Injury Hazard 3. 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. Failure to do so the choke. could result in death or electrical shock. 4. Install the new choke so that it fits tightly into plac
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REMOVING THE CONTROL PANEL 2. Remove the two screws from the top of the cabinet for the vent grille and remove WARNING the grille (see the illustration on page 2-3). Personal Injury Hazard 3. Remove the screw from the top center tab Disconnect from the electrical supply be- of the control panel. fore servicing the unit. Failure to do so 4. From the top and back of the control could result in death or electrical shock. panel, lift the top locking tab and pull 1. Disconnect the electrical supply t
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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 WARNING grille (see the illustration on page 2-3). Personal Injury Hazard 3. Remove the control panel from the micro- wave oven (see page 2-6). Disconnect from the electrical supply be- fore servicing the unit. Failure to do so 4. Without touching the metal ends, unsnap could result in death or electrical sho
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REMOVING/ADJUSTING THE INTERLOCK SWITCHES 5. Remove the center screw from the fan cover and fold the cover back so you can WARNING access the switches (see the illustration below). Personal Injury Hazard 6. Remove the two mounting screws from Disconnect from the electrical supply be- the interlock switch assembly, and posi- fore servicing the unit. Failure to do so tion the assembly so you can easily ac- could result in death or electrical shock. cess the switches and wiring. 7. Refer to inset 1
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Original 03/97 Microwave Oven Hood Combo Service Manual — LIT 4317216 Page 2-9 INSET 2 1. PUSH THIS LOCKING ARM BACK TO UNLOCK INSET 1 SWITCH. 1. RAISE THIS LOCKING ARM TO RELEASE SWITCH FROM HOUSING. 2. PRESS BODY IN ALL OTHER SECONDARY SWITCHES THIS DIRECTION TO INTERLOCK SWITCH REMOVE SWITCH 2. ROTATE SWITCH ON THIS FROM HOUSING. PIN AND REMOVE SWITCH FROM HOUSING. NOTE: THESE POSTS HOLD THE SWITCH IN PLACE ON THE HOUSING AND ARE STATIONARY. INTERLOCK SWITCH HO
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LATCH MAKING ADJUSTMENTS HOUSING 1. 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 will blow the line fuse. CHECK GAP SECONDARY HERE INTERLOCK 2. Close and secure the fan cover with its SWITCH mounti