Whirlpool 1997 E User Manual

SERVICE MANUAL

for the

OVER-THE-RANGE

MICROWAVE OVEN HOOD

COMBINATION

1997 “E” Models

March, 1997

Printed in U.S.A. LIT4322167

THIS MANUAL CONTAINS INFORMATION NECESSARY FOR SERVICING THE WHIRLPOOL MICROWAVE OVEN HOOD COMBINATION , MODELS:

MH7130XE MH7135XE MH9115XE

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 C22.1 CANADIAN ELECTRICAL CODE, PART 1

This Microwave Service Manual is for authorized WHIRLPOOLSM service technicians only.

Because of the high voltage and the critical nature of the door closure system for the microwave oven, Whirlpool recommends that customers DO NOT service their own microwave oven.

If you encounter problems with any Whirlpool range having a microwave feature, call your nearest authorized WHIRLPOOLSM Service Company for service.

Cooking Products Service Manual

Original March, 1997 4322167

Page iii

TABLE OF CONTENTS

Page

Important Safety Information ...............................................................................................................................v

Theory Of Operation ......................................................................................................................................... 1-1

Component Access ........................................................................................................................................... 2-1

Component Sections .................................................................................................................................. 2-1

General ...............................................................................................................................................................

Removing The Microwave Oven & Cabinet ............................................................................................ 2-2

The Protection Control System .......................................................................................................................

Removing The Oven Door ......................................................................................................................... 2-4

Removing The Oven Door Components.................................................................................................. 2-5

Removing The Control Panel .................................................................................................................... 2-6

Removing The Line Fuse........................................................................................................................... 2-7

Removing/Adjusting The Interlock Switches .......................................................................................... 2-8

Removing The Base Thermal Fuse........................................................................................................ 2-10

Removing The Magnetron Thermal Fuse .............................................................................................. 2-11

Removing The Convection Thermistor .................................................................................................. 2-12

Removing The Cavity Thermal Fuse ..................................................................................................... 2-14

The Operating Control System......................................................................................................................

Removing The Oven Light Socket.......................................................................................................... 2-15

Removing The Control Circuit Board & The Turntable Indicator Circuit Board ..............................2-16

Removing The Fan Motor ........................................................................................................................ 2-17

Removing The Power Cord .....................................................................................................................2-18

Removing The Blower Motor Capacitor................................................................................................. 2-19

Removing The Convection Heating Element ........................................................................................ 2-20

Removing The Gas Sensor .....................................................................................................................2-22

Removing The Stirrer Motor .................................................................................................................... 2-23

Removing The Turntable Motor .............................................................................................................. 2-24

Removing The Cooktop Light Sockets ..................................................................................................2-25

The High Voltage Components .....................................................................................................................

Accessing The Components.................................................................................................................... 2-26

Removing The Magnetron .......................................................................................................................2-27

Removing The High Voltage Rectifier And The High Voltage Capacitor ......................................... 2-28

Removing The High Voltage Transformer............................................................................................. 2-29

2-2

2-4

2-15

2-26

iii

Page

Component Description & Testing .................................................................................................................. 3-1

Important Safety Instructions .................................................................................................................... 3-1

The Thermal Fuses..................................................................................................................................... 3-4

The Blower Motor Capacitor ..................................................................................................................... 3-5

The Gas Sensor .......................................................................................................................................... 3-6

The Convection Thermistor ....................................................................................................................... 3-7

The Convection Heating Element............................................................................................................. 3-8

Motors ........................................................................................................................................................... 3-9

Programming Checks ............................................................................................................................... 3-10

Charts ......................................................................................................................................................... 3-11

Checking The Microwave Power Output ............................................................................................... 3-14

Checking For Microwave Energy Leakage ...........................................................................................3-15

Component Testing ..................................................................................................................................3-18

Control Circuit Board Checklist ..............................................................................................................3-23

Primary, Monitor, & Secondary Switch Checkout Procedure............................................................. 3-24

Tech Tips ............................................................................................................................................................ 4-1

Wiring Diagrams.......................................................................................................................................... 4-1

Strip Circuits ................................................................................................................................................ 4-3

Specifications .............................................................................................................................................. 4-6

Model & Serial Number Explanation ...................................................................................................... 4-15

Whirlpool Microwave Hood Warranty..................................................................................................... 4-16

IMPORTANT SAFETY INFORMATION

WARNING

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.

The following information is used throughout this manual, and should be read carefully.

NOTE

Cooking Products Service Manual

Original March, 1997 4322167

Fire Hazard

Do not obstruct the flow of ventilation air.

Electrical Shock Hazard

It is the customer’s responsibility to:

• Contact a qualified electrical installer.

Page v

Helpful information that explains a more complicated step, prior to carrying it out.

CAUTION

Information that will help you avoid actions that could cause product damage (scratches, dents, etc.) and damage to personal property.

WARNING

Information that alerts you to potentially dangerous conditions. These conditions can cause serious personal injury (burns, fire and electrical shock, etc.) if the suggested procedures are not observed.

• Assure that electrical installation is adequate and in conformance with the National Electrical Code, ANSl/NFPA 70— latest edition*, and all local codes and ordinances.

Failure to do so could result in fire, electrical shock, or other personal injury.

Take special care when drilling holes into the wall for venting or electrical wiring. Electrical wires may be concealed behind the wall covering.

Failure to do so could result In fire, electrical shock, or other personal injury.

• National Fire Protection Association Batterymarch Park Quincy, Massachusetts 02269

WHIRLPOOL ASSUMES NO RESPONSIBILITY FOR ANY REPAIRS MADE ON OUR PRODUCTS BY ANYONE OTHER THAN AUTHORIZED WHIRLPOOL SERVICE TECHNICIANS.

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 ate repair must be made before continuing to service the unit. Check interlock function by operating the door latch. The oven cook cycle should cut off before the door can be opened.

The door and latching assembly contains the radio frequency energy within the oven. The door is protected by three safety interlock switches. Do not attempt to defeat them. Under no circumstances should you try to operate the oven with the door open.

at 5 cm, appropri-

• Proper operation of the microwave ovens requires that the magnetron be properly assembled to the waveguide and cavity. Never operate the magnetron unless it is properly installed.

• Be sure the “RF” seal is not damaged, and assembled around the magnetron dome properly when installing the magnetron.

• Routine service safety procedures should be exercised at all times.

• Untrained personnel should not attempt service without a thorough review of the test procedures and safety information contained in this manual.

PRECAUTIONS TO BE OBSERVED BEFORE AND DUR-

ING SERVICING TO AVOID POSSIBLE EXPOSURE TO

EXCESSIVE MICROWAVE ENERGY.

1. Do not operate or allow the oven to be operated with the door open.

2. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary:

a)Interlock Operation. b)Proper Door Closing. c) Seal and Sealing Surfaces (Arcing,

Wear, and Other Damage).

d)Damage to or Loosening of Hinges and

Latches.

e)Evidence of Dropping or Abuse.

3. 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.

4. Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner.

5. A microwave leakage check to verify compliance with the Federal performance standard should be performed on each oven prior to release to the owner.

6. Do not attempt to operate the oven if the door glass is broken.

CAUTION

WARNING

Whirlpool microwave ovens have a monitoring system designed to assure proper operation of the safety interlock systems.

Cooking Products Service Manual Original March, 1997 4322167

Page vii

The interlock monitor switch will immediately cause the oven fuse to blow if the door is opened while the following combined failure exists:

Primary door interlock switch and/or secondary interlock switch contacts failed in a closed position.

CAUTION: REPLACE BLOWN FUSE WITH 15 AMPERE CLASS H FUSE ONLY.

Before replacing the blown oven fuse, test the upper and lower door interlock switches, cook relay or latch relay, and interlock monitor switch (middle switch) for proper operation as described in the component test procedures.

DO NOT ATTEMPT TO REPAIR STICKING CONTACTS OF ANY INTERLOCK SWITCH, SAFETY SWITCH, OR COOK (LATCH) RELAY (REPLACE SWITCHES).

Any indication of sticking contacts during component test requires replacement of that component to assure reliability of the safety interlock system.

IF THE FUSE IS BLOWN, THE MONITOR, PRIMARY INTERLOCK AND SECONDARY INTERLOCK SWITCHES MUST ALSO BE REPLACED. BE SURE THEY ARE PROPERLY CONNECTED.

NOTES:

• For proper repair and assembly of the oven door, refer to pages 2-4 and 2-5.

• Interlock switches are not adjustable individually.

• For proper repair and adjustment of the interlock switches, refer to page 2-8.

DISCONNECT FROM POWER SUPPLY BEFORE SERVICING.

CAUTION: HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE. EXTREME CAUTION SHOULD BE OBSERVED AT ALL TIMES.

CAUTION: DO NOT TOUCH OVEN COMPONENTS OR WIRING DURING OVEN OPERATION. ATTACH METER LEADS WITH ALLIGATOR CLIPS WHEN MAKING OPERATIONAL TESTS.

CAUTION: IT IS NEITHER NECESSARY NOR ADVISABLE TO ATTEMPT MEASUREMENT OF HIGH VOLTAGES.

CAUTION: BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING, ALWAYS UNPLUG THE OVEN FROM ITS POWER SOURCE AND DISCHARGE THE CAPACITOR BY USING A 20,000-OHM DISCHARGE RESISTOR.

USE AN INSULATED PLASTICHANDLE SCREWDRIVER AND SHORT ACROSS THE CAPACITOR TERMINALS.

vii

R.F. LEAKAGE TEST

CAUTION

EQUIPMENT

• Electromagnetic energy leakage monitor (NARDA 8100B, HOLADAY H1501).

• 600 ml glass beaker.

• Glass thermometer 100°C or 212° F.

TEST

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.

2. Place a 250 ML (8.0 oz.) glass of water in

the center of the oven bottom.

3. Select “HIGH” cook power, turn the mi-

crowave oven on, and test for R.F. Ieakage at the following locations using the pattern shown below:

a) Around the cabinet at the front. b) Around the door. c) Across the console panel. d) Horizontally across the door. e) Vertically across the door. f) Diagonally across the door. g) Across the air vents. h) Across the rear air vent. i) All lockseams. j) Weld at bottom. k) Bottom plate. I) Oven feet.

4. The scan speed is one inch per second.

When checking for R.F. Ieakage, use an approved R.F. measuring device to assure less than 4 mw/cm 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.

A properly operating door and seal assembly will normally register small emissions, but they must be no greater than 4 mw/cm measurement uncertainty.

NOTE: Enter leakage readings in space BEFORE and AFTER on the service document.

All microwave ovens exceeding the emission level of 4 mw/cm Service for microwave ovens immediately and the owner should be told not to use the microwave oven until it has been repaired completely.

If a microwave oven is found to operate with the door open, report to Dept. of Service, the manufacturer and CDRH* immediately. Also tell the owner not to use the oven.

* CDRH: Center for Device and Radiological Health, Food

and Drug Administration.

The interlock monitor switch acts as the final safety switch protecting the customer from microwave radiation. If the interlock monitor switch operated to blow the fuse when the interlocks failed you must replace all interlock switches—primary and secondary interlock switches and the monitor switch with new ones because the contacts of those interlock switches may be melted and welded together.

All repairs must be performed in such a manner that microwave energy emissions are minimal.

Address for CDRH is:

Office of Compliance (HFZ-312) Center for Devices and Radiological Health

1390 Piccard Drive Rockville, Maryland 20850

emission at 5 cm distance with

to allow for

must be reported to Dept. of

viii

THEORY OF OPERATION

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Page 1-1

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.

The control board uses five relays to operate the various functions of the microwave oven

Relay 4 controls the speed of the blower motor through the contol panel. The base thermal fuse will also turn the blower motor on to its low speed if the temperature reaches 133˚F. The schematic configuration for relay 4 is shown in the following diagram. The relay is explained in further detail on the following page.

(see below). The relays are controlled by the microcomputer on the control board, and per-

(NC)

(C)

(NO)

form the functions shown below.

RELAY 4

Relay 1 ........................................................ Oven Light/Fan & Stirrer Motors

Relay 2 ........................................................ High Voltage Section

Relay 3 ........................................................ Low-Speed Blower Motor

Relay 4 (N.C. Contacts) ........................... Auto Low-Speed Blower Motor

Relay 4 (N.O. Contacts) ........................... High-Speed Blower Motor

Relay 5 ........................................................ Turntable Motor

BASE

THERMAL

FUSE

BLOWER

MOTOR

(LOW)

(HI)

(C)

CN3

CONTROL

CIRCUIT

BOARD

RELAY RY1

RELAY RY5

MICROCOMPUTER

RELAY RY2

RELAY RY4

RELAY RY3

1-1

The normally-closed (N.C.) contacts of relay 4 provide a potential circuit for the Base Thermal Fuse. 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.

20A LINE

FUSE

MAGNETRON

THERMAL

FUSE

CAVITY

THERMAL

FUSE

MICROCOMPUTER

TRANSFORMER

3 1

BOARD

LOW-VOLTAGE

RELAY 4

THERMAL

BASE

FUSE

CAPACITOR

RD RD

BLOWER

MOTOR

(C)(HIGH)

When the low-speed fan is selected by the user at the control panel, relay 3 and the normallyclosed (N.C.) contacts of relay 4, complete the circuit to the low-speed windings of the blower motor and turn it on.

20A LINE

FUSE

RDBK

MAGNETRON

THERMAL

FUSE

CAVITY

THERMAL

USE

MICROCOMPUTER

LOW-VOLTAGE

TRANSFORMER

3 1

BOARD

RELAY 4

RELAY 3

CAPACITOR

PK/W

(LOW)

BLOWER MOTOR

RDRD

(C)

When the high-speed fan is selected by the user at the control panel, the normally-open (N.O.) contacts of relay 4 complete the circuit to the high-speed windings of the blower motor and turn it on.

20A LINE

FUSE

MAGNETRON

THERMAL

FUSE

CAVITY

THERMAL

FUSE

MICROCOMPUTER

TRANSFORMER

3 1

BOARD

LOW-VOLTAGE

RELAY 4

CAPACITOR

RDRD

(HI) (C)

BLOWER MOTOR

1-2

COMPONENT ACCESS

COMPONENT SECTIONS

This section instructs you on how to service the individual components in the Microwave Oven Hood Combination. These components (shown below) and their sections are as follows:

• General

Cabinet

• The Protection Control System

Oven Door Oven Door Components Control Panel Line Fuse Interlock Switches Base Thermal Fuse Magnetron Thermal Fuse Convection Thermistor Cavity Thermal Fuse

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Page 2-1

• The Operating Control System Oven Light Socket Control Circuit Board Turntable Indicator Circuit Board Fan Motor Power Cord Blower Motor Capacitor Convection Heating Element Gas Sensor Stirrer Motor Turntable Motor Cooktop Light Socket

• The High Voltage Components Magnetron Rectifier Capacitor Transformer

Refer to the section on the following pages for the component you wish to service.

GAS SENSOR (NOT ON ALL MODELS)

BLOWER MOTOR CAPACITOR

CAVITY THERMAL FUSE

CONVECTION HEATING ELEMENT (NOT ON ALL MODELS)

BLOWER MOTOR

CONVECTION THERMISTOR

(NOT ON ALL MODELS)

TURNTABLE MOTOR

COOKTOP LIGHTS

SECONDARY INTERLOCK SWITCH

INTERLOCK MONITOR SWITCH

PRIMARY INTERLOCK SWITCH

CONTROL CIRCUIT BOARD

TURNTABLE INDICATOR CIRCUIT BOARD

LINE FUSE

STIRRER MOTOR

OVEN LIGHT

MAGNETRON

THERMAL FUSE

FAN MOTOR

MAGNETRON

HV CAPACITOR

HV RECTIFIER

HV TRANSFORMER

BASE THERMAL FUSE

Base Thermal Fuse ................................................. Closes @ 133˚F/56˚C, resets @ 104˚F/40˚C.

Magnetron Thermal Fuse ...................................... Opens @ 228˚F/109˚C, resets @ 140˚F/60˚C.

Cavity Thermal Fuse .............................................. Opens @ 230˚F/110˚C, resets @ 140˚F/60˚C.

2-1

GENERAL

REMOVING THE MICROWAVE OVEN & CABINET

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

IMPORTANT NOTE: Most of the microwave components can be serviced without removing the unit or its cabinet. They can be accessed by removing the vent grille and the control panel. Before removing the unit or its cabinet, first check the procedure for the component you wish to service to see if it is necessary. If it is necessary to remove the unit and its cabinet to service a component, use the following procedure.

4. Support the front of the microwave oven and remove the two bolts and washers from the top of the oven.

5. Using two people, remove the microwave oven from its mounting location and set it on a protected (padded) work surface.

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. Remove the six screws from the base plate and lower it, (see the illustration on the next page), then disconnect the cooktop light connector, and set the base plate aside.

3. Remove the lock pin and washer from the top of the microwave oven.

LOCK PIN & WASHER

6. To remove the vent grille from the microwave oven, remove the two inside screws from the top of the cabinet, then pull the top of the vent grille out so the two center tabs are free of their slots, and remove the grille.

7. Remove the screw from the power cord cover and remove the cover.

8. Remove the remaining screws from the top and rear of the cabinet.

9. Slide the cabinet back and unhook the sides from the tabs, then slide the power cord out of the cabinet, and remove the cabinet.

Proceed to the section for the component you wish to service.

2-2

VENT

GRILLE

CABINET

SCREW

VENT

GRILLE

SCREWS (2)

TAB SLOTS

Cooking Products Service Manual Original March, 1997 4322167

CABINET

Page 2-3

POWER

CORD

POWER

CORD COVER

CABINET

SCREWS

BASE

PLATE

CONNECTORS

SLOTS

BASE PLATE

SCREWS

(6)

COOKTOP LIGHT

ASSEMBLY WIRING

Removing The Cabinet

2-3

THE PROTECTION CONTROL SYSTEM

REMOVING THE OVEN DOOR

WARNING

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.

LIFT DOOR PINS

OUT OF HINGE HOLES

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. Open the oven door all the way, then lift the door pins out of the hinge holes and remove it.

4. Install the new oven door and the vent grille on the microwave oven.

PINS

HINGES

2-4

REMOVING THE OVEN DOOR COMPONENTS

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

Cooking Products Service Manual Original March, 1997 4322167

Page 2-5

4. To remove the oven door choke, use a putty knife along the edges, and pry the choke out from around the inside window frame.

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. Open the oven door all the way, then lift the door pins out of the hinge holes and remove it (see the illustration on the previous page).

SLOT

HOOKED TAB

GLASS HOOK SPRING OVER TABS

LATCHES

FRAME

OVEN DOOR

PRY OUT CHOKE

5. To replace the latches and door glass assembly, remove the two mounting screws from the end of the glass frame, then push the top and bottom edges of the door out and unsnap the locking tabs from the frame and remove the assembly.

6. Slide the latches down and remove the hooked tabs from the slots in the door frame, then unhook the ends of the spring from the door, and remove the latches.

7. Reassemble the oven door.

8. Reinstall the oven door and vent grille on the microwave oven.

FRAME SCREWS

TOP LOCKING TABS

GLASS FRAME

BOTTOM LOCKING TABS

2-5

REMOVING THE CONTROL PANEL

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

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, then lift the panel so that the bottom tabs are out of the slots and pull it forward.

1. Disconnect the electrical supply to the microwave oven.

TURN PANEL OVER

CONTROL PANEL

4. Turn the panel over and disconnect the three harness connectors from the board, then set the control panel aside.

CONTROL

PANEL SCREW

BOTTOM

TABS

BOTTOM

SLOTS

2-6

REMOVING THE LINE FUSE

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

Cooking Products Service Manual Original March, 1997 4322167

Page 2-7

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 control panel from the microwave oven (see page 2-6).

4. From inside the control panel opening, unsnap and open the fuseholder halves.

1. Disconnect the electrical supply to the microwave oven.

CONTROL PANEL

OPENING

5. Remove the line fuse from the fuseholder and pull the wire connectors off the ends.

6. Install the new line fuse and reassemble the microwave oven.

2-7

SLIDE WIRE CONNECTORS

OFF ENDS OF FUSE

LINE FUSE

OPEN FUSEHOLDER

SECTIONS

FUSE HOLDER

REMOVING/ADJUSTING THE INTERLOCK SWITCHES

6. One at a time, pull the wire connectors off

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

REMOVING A SWITCH

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. Remove the control panel from the microwave oven (see page 2-6).

4. Remove the two mounting screws from the interlock switch assembly, and position the assembly so you can easily access the switches and wiring.

5. Refer to inset 1 on the next page for the secondary interlock switch, or inset 2 for any of the other switches mounted on the interlock switch housing assembly, and remove the switch from the housing as shown.

CONTROL PANEL

OPENING

the defective switch, and reconnect them to the same terminals on the replacement switch.

7. Snap the new switch into place on the switch housing.

8. Mount the interlock switch assembly to the chassis flange with two screws.

9. Close the housing cover and secure it with its mounting screw.

MAKING ADJUSTMENTS

1. Plug in the microwave oven and check the operation of the switches. If necessary, loosen the two housing screws, and adjust the 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. Unplug the oven again when you have completed the checks.

2. Reassemble the microwave oven.

INTERLOCK

2-8

SCREW

INTERLOCK

SWITCH

HOUSING

INTERLOCK

SCREW

INSET 1

SECONDARY

INTERLOCK

SWITCH

INTERLOCK SWITCH

HOUSING ASSEMBLY

RAISE THIS LOCKING ARM TO RELEASE SWITCH FROM HOUSING.

PRESS BODY IN THIS DIRECTION TO REMOVE SWITCH FROM HOUSING.

Cooking Products Service Manual Original March, 1997 4322167

INSET 2

ALL OTHER

SWITCHES

NOTE: THESE POSTS HOLD THE SWITCH IN PLACE ON THE HOUSING AND ARE STATIONARY.

SECONDARY INTERLOCK

SWITCH

PUSH THIS LOCKING ARM BACK TO UNLOCK SWITCH.

ROTATE SWITCH ON THIS PIN AND REMOVE SWITCH FROM HOUSING.

Page 2-9

WHITE (H.V. Transformer)

SMALL WHITE (Monitor Switch)

LARGE WHITE (Power Cord)

SMALL WHITE (Oven Lamp)

INTERLOCK MONITOR

PRIMARY INTERLOCK

SWITCH

WHITE (Turntable Motor)

WHITE (Secondary Switch)

RED (H.V. Transformer)

PINK (CN2 Pin 1)

Blue (CN2 Pin 3)

Interlock Switch Wiring

2-9

REMOVING THE BASE THERMAL FUSE

CONTROL PANEL

OPENING

YELLOW

PINK WHITE

BASE

THERMAL FUSE

WARNING

Personal Injury Hazard

Disconnect from the electrical supply before servicing the unit. Failure to do so could result in death or electrical shock.

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 control panel from the microwave oven (see page 2-6).

4. Remove the mounting screws from the base thermal fuse and remove it.

1. Disconnect the electrical supply to the microwave oven.

5. Unplug the connectors from the terminals of the base thermal fuse.

6. Install the new base thermal fuse and reassemble the microwave oven.

THE BASE THERMAL FUSE CLOSES

AT 133˚F & RESETS @ 104˚F.

2-10

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Page 2-11

REMOVING THE MAGNETRON THERMAL FUSE

4. Unplug the line cord connector and re-

WARNING

Personal Injury Hazard

move the line cord.

5. Unplug the connector from the terminals of the fan motor.

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 microwave oven from its mounting location (see page 2-2).

3. Remove the vent grille and cabinet from the microwave oven (see the illustration on page 2-3).

REMOVE FIVE

AIR DUCT SCREWS

6. Remove the five screws from the air duct.

7. Lift the air duct and position it so that you can access the magnetron thermal fuse, then remove the mounting screw, and unplug the connectors from its terminals.

8. Install the new magnetron thermal fuse on the air duct, and reassemble the microwave oven.

BOTTOM

OF AIR DUCT

MAGNETRON

THERMAL FUSE

THE MAGNETRON THERMAL FUSE

OPENS AT 228˚F & RESETS @ 140˚F.

2-11

UNPLUG POWER

CORD & FAN MOTOR

BLACK & RED

WIRES

REMOVING THE CONVECTION THERMISTOR

WARNING

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 microwave oven from its mounting location (see page 2-2).

3. Remove the vent grille and cabinet from the microwave oven (see the illustration on page 2-3).

4. Remove the five screws from the air duct and position it so that you can access the pulley cover underneath.

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. Cover the spliced wire ends with electrical tape so that they cannot short to the oven.

9. Mount the new convection thermistor to the oven and reassemble the microwave oven.

2-12

BRACKETS

Cooking Products Service Manual Original March, 1997 4322167

CIRCULATION

PULLEY COVER

Page 2-13

SENSOR

COVER

PHILLIPS

SCREW

REMOVE FIVE

AIR DUCT SCREWS

WHITE WIRES

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

2-13

REMOVING THE CAVITY THERMAL FUSE

3. Remove the vent grille and cabinet from

WARNING

Personal Injury Hazard

the microwave oven (see the illustration on page 2-3).

4. Remove the five screws from the air duct.

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 microwave oven from its mounting location (see page 2-2).

THE CAVITY THERMAL FUSE OPENS AT 230˚F

CAVITY

THERMAL

FUSE

AIR DUCT

AND RESETS AT 140˚F

5. Unplug the connectors from the terminals of the cavity thermal fuse, then lift the left side of the air duct, and remove the cavity thermal fuse. NOTE: There are no mounting screws holding the cavity thermal fuse in place.

6. Install the new cavity thermal fuse in its mounting hole, and reassemble the microwave oven.

REMOVE FIVE

AIR DUCT SCREWS

2-14

+ 56 hidden pages