삼 정 흥 판 MODEL 721.66339 DIVISION 20 BASIC FIELD MANUAL FOR MICROWAVE OVEN MODEL 721.
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.
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 721.66339 MECHANICAL SERVICE INFORMATION TABLE OF CONTENTS 1.
ADJUST THE LATCH AND SWITCH CLOSING 1. ADJUSTMENT PROCEDURES To avoid possible exposure to microwave energy leakage, adjust the door latches and interlock switches, using the following procedure. (3) Loosen the two screws holding the plastic latch board as shown. (4) With the oven door closed tightly, move the latch board upward toward the top of the oven and/or away from the door latch until the gaps are less than 1/64” (0.5 mm). ONLY AUTHORIZED SERVICE PERSONNEL SHOULD MAKE THIS ADJUSTMENT.
LATCH BOARD SECONDARY INTERLOCK SWITCH DOOR LATCH A MONITOR INTERLOCK SWITCH PRIMARY INTERLOCK SWITCH DOOR LATCH Figure 1-a LATCH 0-1/64" LATCH BOARD 0-1/64" -4- Figure 1-b
2. PRECAUTIONS ON INSTALLATION 4. TRIAL OPERATION (Figure 2) A. Plug the power supply cord into a 120 V AC, 60 Hz, single-phase power source with a capacity of at least 20 amperes. B. Since the unit weights about 36.5 lbs, be sure to place it on a sturdy and flat surface. C. Avoid placing the unit in a location where there is direct heat or splashing water. D. Place the unit as far away as possible from TV, radio, etc. to prevent interference.
SPECIFICATIONS Rated Power Consumption ..........................................1650W maximum Output ..........................................................................1200W maximum (*IEC 60705 Rating standard) ...................................................................Adjustable 100W through 1200W, 11 steps Frequency ....................................................................2,450 MHz ± 50 MHz Power Supply ...............................................................
-7- NOTICE: SINCE THIS IS BASIC SCHEMATIC DIAGRAM, THE VALUES OF COMPONENTS AND SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT. IMPORTANT SAFETY NOTE: THE SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION, FIRE, ELECTRICAL SHOCK, AND HAZARDS. WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER S SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAGRAM. 6.
B.
7. OPERATING PROCEDURES A. OVEN CONTROL PANEL Figure 5 1. DISPLAY. The display includes a clock and indicators that tell you time of day, cooking time settings, and cooking functions selected. 2. QUICK TOUCH SENSOR. This pad allows you to cook most of your favorite foods without having to select cooking times and power levels. 3. MORE / LESS. All of the one touch cook and Timed Cook can be adjusted to cook food for a longer or shorter time. MORE Press MORE will add 10 seconds to the cooking time.
(6) TIMED COOKING 1. Touch STOP/CLEAR. 2. Touch COOK TIME. 3. Touch number for cooking time. 4. Touch POWER. 5. Touch number for cooking power level. 6. Touch START. B. EASY USE TABLE (1) KITCHEN TIMER 1. Touch STOP/CLEAR. 2. Touch KITCHEN TIMER. 3. Touch correct number for time. 4. Touch START. (7) MULTI-STAGE COOKING 1. Touch STOP/CLEAR. 2. Touch COOK TIME. 3. Touch number for cooking time. 4. Touch POWER. 5. Touch number for cooking power level. 6. Repeat steps 2-5 to set 2nd cooking stage. 7.
8. PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE A. CAUTIONS (1) Be sure to check a microwave emission prior to servicing the oven if the oven is operative prior to servicing. (2) The service personnel should inform the manufacturer, importer, or assembler of any certified oven unit found to have a microwave emission level in excess of 5mW/cm.sq. and should repair any unit found to have excessive emission levels at no cost to the owner and should ascertain the cause of the excessive leakage.
G. POWER OUTPUT MEASUREMENT (1) Fill the test beaker with 59 ˚F(15 ˚C) ~ 75 ˚F(24 ˚C) 1 liter tap water. (2) Stir the water in the beaker with thermometer ( ˚F or ˚C) and measure temperature as T1. (3) Place the beaker on the center of turntable. (4) Set for one (1) minute and three (3) seconds and operate the oven at high power. NOTE: The additional three (3) seconds is to allow the magnetron to begin generating power.
9. DISASSEMBLY INSTRUCTIONS (6) Pull down and remove the circuit board from the control panel. (7) Remove the F.P.C connector from the terminal socket. IMPORTANT NOTES: UNIT MUST BE DISCONNECTED FROM ELECTRICAL OUTLET WHEN MAKING REPAIRS, RE-PLACEMENTS, ADJUSTMENTS AND CONTINUITY CHECKS. WAIT AT LEAST ONE MINUTE, UNTIL THE HIGH VOLTAGE CAPACITOR IN THE HIGH VOLTAGE POWER SUPPLY HAS FULLY DISCHARGED. THE CAPACITOR SHOULD BE DISCHARGED BY USING INSULATED WIRE - I.E.
C. DOOR ASSEMBLY / REMOVAL (1) Open the door. (2) Remove the choke cover very carefully with a flat-blade screwdriver. CAUTION : Be careful not to damage door seal plate by screwdriver. (3) Lift up and push the door. Remove choke cover NOTE: 1. After replacing the door, be sure to check that the primary switch, monitor switch, and secondary switch operate normally. 2. After replacing the door, check for microwave energy leakage with a survey meter. Microwave energy must be below the limit of 5 mW/cm.sq.
D. MAGNETRON REMOVAL (1) Disconnect the wire lead from the magnetron. (2) Carefully remove the mounting screws holding the magnetron and the waveguide. (3) Remove the magnetron assembly until the tube is clear from the waveguide. E. REMOVING THE TURNTABLE MOTOR 1) Remove the turntable and rotating ring. 2) Lay the unit down on its back. 3) Remove the turntable motor cover. The turntable base cover is easily removed by pinching the eight parts with a wire cutting.
F. HIGH VOLTAGE TRANSFORMER REMOVAL 1) Discharge the high voltage capacitor. 2) Disconnect the leadwire from magnetron, high voltage transformer, and capacitor. 3) Remove the screw holding the high voltage transformer to the baseplate. I. REMOVING SENSOR 1) Disconnect the leadwire from PCB Assembly. 2) Remove a screw securing the sensor duct. G. FAN MOTOR ASSEMBLY / REMOVAL 1) Discharge the high voltage capacitor. 2) Disconnect the leadwire from fan motor and high voltage capacitor.
J. INTERLOCK SYSTEM 1) INTERLOCK MECHANISM The door lock mechanism is a device which has been specially designed to eliminate microwave activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave leakage. 2) MOUNTING OF THE PRIMARY/MONITOR/ SECONDARY SWITCHES TO THE LATCH BOARD 3) INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY • Mount the latch board to the oven assembly.
10. INTERLOCK CONTINUITY TEST WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS. TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-62, VP-532A-OF OR V-5220Q FOR MONITOR SWITCH TYPE NO. SZM-V 15-FA-63, VP-533A-OFF OR SECONDARY SWITCH A.
11. TEST AND CHECKOUT PROCEDURES, 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 WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. 2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF WATER IN CONTAINER) IN THE OVEN. A.
COMPONENTS TEST PROCEDURE RESULTS Antenna Gasket Chassis Filament NOTE: When testing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition. HIGH VOLTAGE CAPACITOR HIGH VOLTAGE DIODE NOTE : Some inexpensive meters may indicate infinite resistance in both direction. Measure the resistance. (Ohm-meter scale: Rx1000) • Terminal to terminal. Normal: Momentarily indicates several ohms, and then gradually returns to infinite.
COMPONENTS RELAY 2 TEST PROCEDURE RESULTS Check for continuity of relay 2 with an ohmmeter. (Remove wire leads from relay 2 and operate the unit.) Relay 2 FAN MOTOR (Wire leads removed) POWER LEVEL 1 2 3 4 5 6 7 8 9 10 4 sec 6 sec 8 sec 10 sec 12 sec 14 sec 16 sec 18 sec 20 sec 22 sec 18 sec 16 sec 14 sec 12 sec 10 sec 8 sec 6 sec 4 sec 2 sec 0 sec Normal: A: Approx. 85 ~ 100 ohm. B: Approx. 10 ~ 25 ohm. Measure the resistance. (Ohm-meter scale: R x 1) B Abnormal: Infinite or several ohm.
B. CHECKOUT PROCEDURES (1) CHECKOUT PROCEDURES FOR FUSE BLOWING CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE. PROBLEMS Fuse blows immediately after the door is closed. Fuse blows immediately after the door is opened. Fuse blows when the door is closed and START key is touched. CAUSES Improper operation of the primary interlock, secondary interlock switches and/or the interlock monitor switch.
(2) CHECKOUT PROCEDURES FOR RELAY - PROBLEM (A) FAN motor and oven lamp turn on without touching START key when the door is closed. NO GOOD YES Remove the mate connector of I/O CON from the circuit board does the unit still operate? NO Replace the circuit board - PROBLEM (B) FAN motor and oven lamp turn on When the door is closed and START key is touched. NO YES Check the interlock switches GOOD NO Replace the micro switches.
(3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit board. (1) The start function fails to operate but the high voltage Systems, the interlock switches, the door sensing and the relay check good. (2) The unit with a normal relay continuously operates. (3) The buzzer does not sound or continues to sound. (4) Some segments of one or more digits do not light up, or they continue to light up, or segments light when they should not. (6) Wrong figures appear.
C. TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL. CAUTIONS 1. Check grounding before checking for trouble. 2. Be careful of the high voltage circuit. 3. Discharge the high voltage capacitor. 4.
(TROUBLE 1) The following visual conditions indicate a probable defective control circuit. 1. Incomplete segments. • Segment missing. • Partial segment missing. • Digit flickering (NOTE: Slight flickering is normal.) 2. Colon does not turn on or blink. 3. A distinct change in the brightness of one or more numbers in display. 4. One or more digits in the display are not lighting. 5. Display indicates a number different from one touched, for example, key in 5 and 3 appears in the display. 6.
(TROUBLE 2) Oven does not operate at all, Display window does not display any figures, and no input is accepted. CONDITION 1. Fuse blows. CHECK Check continuity of monitor switch (with door closed). RESULT CAUSE REMEDY Malfunction of the monitor switch. Replace fuse, primary, monitor switches, and RELAY(RY2) of P.C.B Assembly. Shorted contact at the primary switch. Replace fuse, primary, monitor switches, and RELAY(RY2) of P.C.B Assembly. Normal. Defective high voltage capacitor.
(TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired program times are set and START pad is touched. CONDITION CHECK 1. Setting time does not count down when touching START pad. Check continuity of secondary switch (with door closed). 2. Fan motor or oven lamp do not turn on. RESULT No continuity. CAUSE REMEDY Defective secondary switch. Replace secondary switch. Continuity. Check the connection between CN1 connector and PCB assembly.
(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run. (Display operates properly) CONDITION No microwave oscillation. CHECK Disconnect the wire leads from relay 2 and check continuity of relay 2. (Operate the unit) Check high voltage transformer RESULT No continuity. CAUSE REMEDY Defective PCB assembly. Replace PCB assembly. Defective high voltage transformer. Replace high voltage transformer. Defective high voltage capacitor. Replace high voltage capacitor.
#EV# EXPLODED VIEW INTRODUCTION SENSOR OUTER CASE INTERIOR DOOR BASE PLATE LATCH BOARD CONTROL PANEL -30-
#EV# DOOR PARTS 1013 1005 1004 1002 1000 1003 1001 1006 1007 -31-
#EV# CONTROLLER PARTS 2004 2381 2002 2006 W106 2000 -32-
#EV# OVEN CAVITY PARTS W103 3001 3003 3034 W107 3002 3009 3008 W105 -33-
#EV# LATCH BOARD PARTS W102 4001 4002 4000 4003 4002 4004 -34-
#EV# INTERIOR PARTS W101 5014 5010 5001 5016 5041 3006 5012 W109 5003 W208 5007 W109 W110 W101 5000 3007 W101 5002 5015 5009 W208 W109 9000 W101 5006 -35- 5018
#EV# BASE PLATE PARTS 5008 6000 6001 6007 W101 W108 -36-
#EV# SENSOR PARTS W108 W136 5011 5004 -37-
P/NO: MFL30502909 Printed in Korea
