Related Manuals for Sears 721.88502800
Summary of Contents for Sears 721.88502800
- Page 1 MODEL 721.88502 721.88503 721.88509 DIVISION 22 BASIC FIELD MANUAL MICROWAVE HOOD COMBINATION MODEL 721.88502800 721.88503800 721.88509800 June, 2008...
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Page 2: Warning To Service Technicians
CAUTION WARNING TO SERVICE TECHNICIANS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY a. Do not operate or allow the oven to be operated with the door open. b. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary;... -
Page 3: Table Of Contents
FOREWORD Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing yourself to the Microwave Energy normally contained within the oven cavity. MODEL 721.88502800 721.88503800 721.88509800 TABLE OF CONTENTS (Page) SAFETY PRECAUTIONS ........................Inside front page SPECIFICATIONS ..............................1-1... -
Page 4: Specifications
SPECIFICATIONS Rated Power Consumption ........1750W maximum (Microwave oven+Cook top lamps+Ventilation fan) Microwave Output ..........1100W (IEC60705) Frequency ............2,450 MHz ±50 MHz Power Supply .............120 VAC, 60 Hz Rated Current ............14.5 Amp. (Microwave oven+Cook top lamps+Ventilation fan) Magnetron Cooling ..........Forced Air Cooling Rectification ............Rectification Voltage Double Half-Wave Door Sealing ............Choke System Safety Devices ...........Magnetron Thermostat: Open at 293... -
Page 5: Cautions
CAUTIONS Unlike other appliances,the microwave oven is MICROWAVE RADIATION high-voltage and high-current equipment. Personnel should not be exposed to the Though it is free from danger in ordinary use, microwave energy which may radiate from the extreme care should be taken during repair. magnetron or other microwave generating device if it is improperly used or connection. -
Page 6: Installations
INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY. PRECAUTIONS ON INSTALLATION A. Plug the power supply cord into a 120V AC, 60Hz, single-phase power source with a capacity of at least 20 amperes. B. Avoid placing the unit in a location where there is direct heat or splashing water. -
Page 7: Operating Instructions
OPERATING INSTRUCTIONS CONTROL PANEL... -
Page 8: Control Panel Instructions
CONTROL PANEL INSTRUCTIONS 1. Display Screen shows the time of day and cook mode 9. SOFTEN. Touch this pad to soften Butter, Cream when the microwave oven is not in use. During Cheese, Frozen Juice, Ice Cream. programming, it displays function menus for you to MELT. -
Page 9: Overall Circuit Diagram
OVERALL CIRCUIT DIAGRAM SCHEMATIC DIAGRAM... -
Page 10: Matrix Circuit For Touch Key Board
MATRIX CIRCUIT FOR TOUCH KEY BOARD... -
Page 11: General Information For Service
GENERAL INFORMATION FOR SERVICE GENERAL PRECAUTIONS IN USE FEATURES AND SPECIFICATIONS FEATURES A. Never operate the unit when it is empty. Operating the oven with no load may shorten the life of the A. The safety systems incorporated in this model are: magnetron. -
Page 12: Service Information
SERVICE INFORMATION PRECAUTIONS AND REPAIR SERVICE TIPS PRELIMINARY (3) Do not operate the unit until it is completely repaired, if any of the following conditions exist. The unit must not be operated. A. SINCE NEARLY 4000 VOLTS EXISTS IN SOME (a) The door does not close firmly. -
Page 13: Microwave Leakage Test
MICROWAVE LEAKAGE TEST CAUTIONS EQUIPMENT- • Be sure to check microwave leakage prior to • TESTER (VOLTS-DC, AC, Ohmmeter) servicing the oven if the oven is operative prior to • Microwave survey meter servicing. - Holaday HI-1500 • The service personnel should inform the HI-1501 manufacture importer, or assembler of any certified - Narda... -
Page 14: Power Output Measurement
MEASUREMENT WITH THE OUTER CASE NOTE WHEN MEASURING REMOVED (1) Do not exceed meter full scale deflection. (2) The test probe must be removed no faster than (1) When you replace the magnetron, measure for 1 inch/sec (2.5cm/sec) along the shaded area, microwave energy leakage before the outer case otherwise a false reading may result. -
Page 15: Disassembly Instructions
DISASSEMBLY INSTRUCTIONS (4) Remove 3 screws securing the circuit board. IMPORTANT NOTES: UNIT MUST BE DISCONNECTED FROM ELEC- TRICAL OUTLET WHEN MAKING REPAIRS, RE- PLACEMENTS, ADJUSTMENTS AND CONTIN- UITY CHECKS. WHEN RECONNECTING THE WIRE LEADS TO Circuit Board ANY PART, MAKE SURE THE WIRING CONNE- CTIONS AND LEAD COLORS ARE CORRECTLY MATCHED ACCORDING TO THE OVERALL CIR- CUIT DIAGRAM. - Page 16 HOW TO REMOVE THE F.P.C. CONNECTOR HOW TO INSERT THE F.P.C. CONNECTOR Follow the steps below as illustrated in Figures 4 Follow the steps below as illustrated in Figures 6 and 5 to remove the F.P.C. connector. and 7 to insert the F.P.C. connector. (1) Insert the F.P.C.
- Page 17 B. REMOVING THE OUT CASE(Figure 8) (1) Remove the vent grille by removing two screws securing it to the out case. (2) Remove two screws securing it to the air duct. (3) Remove the mounting plate by turning the screws (1 or 2 screws) securing it to the out case.
- Page 18 C REMOVING THE DOOR INTERLOCK SWITCHES (Figures 9,10) (1) Disconnect the wire leads from the interlock switches. (2) Remove two screws securing the Latch Board. (3) Make necessary replacements and check microwave energy leakage according to “ADJUSTMENT PROCEDURES” on page 7-12. Fan Motor) RD(from turntable Motor) WIRE COLOR...
- Page 19 D. REMOVING MAGNETRON • When replacing the magnetron, be sure to install the magnetron gasket in the correct position and be sure (Figures 11 Through 12) that the gasket is in good condition. (1) Remove the vent grille by loosening two screws. (Figure 11) •...
- Page 20 E. REMOVING STIRRER FAN F. REMOVING DOOR (Figure 15) (Figures 13 and 14) (1) Remove the vent grille by two screws securing it (1) Remove two screws securing it to the oven to the outcase loosening. upper plate. (2) Lift up and draw the door. (2) Pull out the stirrer fan cover.
- Page 21 H. ASSEMBLING DOOR (3) Carefully pull the ventilation motor ASS'Y out of the microwave oven. (See Figure 18-b) (1) When mounting the door assembly to the oven assembly, be sure to adjust the door assembly parallel to the chassis. Also adjust so the door has no play between the inner door surface and oven frame assembly.
- Page 22 J. REMOVING THE TURNTABLE MOTOR K. REPLACING THE HUMIDITY SENSOR (1) Remove the glass tray and rotating ring. (1) Remove the sensor by removing two screws (2) Remove the turntable shaft VERY CAREFULLY securing it to the air duct. (See Figure 22) by hand.
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Page 23: Interlock System
INTERLOCK SYSTEM INTERLOCK MECHANISM The door lock mechanism is a device which has been specially designed to eliminate completely microwave activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave leakage. ADJUSTMENT PROCEDURES CHECK THE DOOR LATCH AND SWITCH To avoid possible exposure to microwave energy CLOSING. - Page 24 TEST THE LATCH AND SWITCH SEQUENCE (7) When you achieve the proper sequence of (5) Open the oven door slowly. Watch the door latch, switches in Steps 5 and 6, tighten the latch board the Secondary Switch. Release Rod and Lever screws at that point.
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Page 25: Interlock Continuity Test
INTERLOCK CONTINUITY TEST A. PRIMARY INTERLOCK SWITCH TEST B.S ECONDARY INTERLOCK SWITCH TEST When the door is opened slowly,an audible click Disconnect the wire lead from the secondary should be heard at the same time or successively switch. at intervals and the latches should activate the Connect the ohmmeter leads to the common switches with an audible click (COM)and normally open (NO)terminals of the... -
Page 26: Test And Checkout Procedures And Troubleshooting
TEST AND CHECKOUT PRECEDURES AND TROUBLESHOOTING CAUTIONS 1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT.PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE LEAD WIRES FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. 2. - Page 27 COMPONENTS TEST RESULTS 1. Remove wire leads. CAPACITOR 2. Measure resistance. (ohm meter scale: Rx1000) • Terminal to terminal Normal: Momently indicates several ohm, and then gradually returns to infinite • Terminal to case Normal: Infinite. 1. Measure continuity. Forward. Normal:Continuity.
- Page 28 COMPONENTS TEST RESULTS 1.Remove lead wires. Normal: VENTILATION MOTOR 2.Measure resistance. Approximately 20 to 40 ohms (ohm meter scale:Rx1) Abnormal:Infinite Normal: Approximately 1. Remove wire leads. TURNTABLE MOTOR 2.0 to 3.0 Kohms 2. Measure resistance. Abnormal: (ohm meter scale: Rx1000) Infinite or several.
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Page 29: A.test Procedures
KEY MATRIX COMPONENTS TEST PROCEDURES RESULTS Measure the resistance between terminal TOUCH KEY BOARD When When not pins of connector KEY CONNECTOR. touched touched NOTE: Resistance When reconnecting the FPC connector, value More than Less than make sure that the holes on the FPC 1 mega ohm 400 ohms connector are properly engaged with hooks... -
Page 30: B.checkout Procedures
B. CHECKOUT PROCEDURES (1) CHECKOUT PROCEDURES FOR FUSE BLOWING CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE. PROBLEMS CAUSES Fuse blows immediately after the door is closed. Improper operation of the primary interlock, secondary Fuse blows immediately after interlock switches and/or the interlock monitor switch. the door is opened. - Page 31 (2)CHECKOUT PROCEDURES FOR RELAY. -PROBLEM (A)- -PROBLEM (A)-- FAN motor turns on without touching START key Oven lamp turns on without touching START key when the door is closed. when the door is closed. Remove the mate connector of I/O Remove the mate connector of I/O GOOD GOOD...
- Page 32 (3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit 5) Some segments of one or more digits do not light board. up, or they continue to light up, or segments light 1) Check the input current.If the input current is more when they should not.
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Page 37: Exploded View
#EV# EXPLODED VIEW DOOR PARTS (I) FOR MODELS: 1005 1004 1000 1008 1382 W171 1007 1011 1006 W109 1009 -8-1-... - Page 38 #EV# CONTROLLER PARTS (I) FOR MODELS: 2004 2381 2006 W130 2008 2002 W136 2000 2030 2400 2021 2041 W136 2009 2007 MBM2 -8-3-...
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Page 39: Oven Cavity Parts
#EV# OVEN CAVITY PARTS W142 W142 3010 W142 3024 3031 W109 3003 3029 3001 3102 6009 W202 W178 3032 6000 5382 3036 3005 3037 3011 3018 9000 W121 3025 3026 -8-5-... -
Page 40: Latch Board Parts
#EV# LATCH BOARD PARTS 4000 4002 W102 4001 4003 4002 4004 -8-6-... - Page 41 #EV# INTERIOR PARTS (I) 3002 3381 Roller part is Tray Assembly Included. W110 Back 5008 5012 W109 W101 5003 5007 W108 5000 5002 5049 W210 5018 5058 5024 5009 W101 5043 5023 5062 W108 3009 W105 3007 W173 W109 5051 W109 -8-7-...
- Page 42 #EV# INTERIOR PARTS (II) 5707 W150 3027 W150 5027 W144 W109 5011 5016 5001 5041 W178 5412 5045 5800 3005 5006 W202 5010 5014 5382 5029 5037 -8-8-...
- Page 43 #EV# INSTALLATION PARTS 6008 6011 6010 6009 COOKING MFL1 MFL3 MEZ1 MBM4 MBM5 INSTALLATION TEMPLATE TEMPLATE & GUIDE MANUAL UPPER WALL CARE LABEL -8-9-...
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Page 44: Exposure To Excessive Microwave Energy
MODEL NO : 88502 / 88503 / 88509 Component tests TECH-SHEET _ RETAIN FOR SERVICE TECHNICIAN ONLY L.V. TRANS- Personal Injury/Product Damage FORMER OVEN WARNING THERMOSTAT Disconnect the power supply cord from the Conduct a microwave energy test after CONDENSER Electrical Shock Hazard outlet before removing the outer cabinet performing any test or repairs to the... - Page 45 High voltage components High voltage components Components Test Results Components Test Results Components Test Results H.V.Diode (RECTIFIER) STEP 1. Test the diode to see if it is shorted. Magnetron Absolute Humidity 1. Remove wire leads. Install the magnetron seal 1. Disconnect sensor connector from Normal: Procedure: in the correct position.
- Page 46 Complete the following steps before checking microwave circuitry: 1. Check the line voltage, household fuse or circuit breaker. 2. Check for loose wiring or mis-wiring within microwave. 3. Disconnect white wire from high-voltage transformer and discharge high-voltage capacitor. NOTE: 1. All testing must be done with an ohmmeter having a sensitivity of 20,000 ohm per volt or greater and powered by at least a 9-volt battery.
- Page 47 P/NO : MFL57016001 Printed in Korea...
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