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R-2397
SERVICE MANUAL
S5708R2397H/X
COMMERCIAL
MICROWAVE OVEN
MODEL
R-2397
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
TABLE OF CONTENTS
Page
CAUTION, MICROWAVE RADIATION ...................................................................................................... 1
WARNING .....................................................................................................................
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R-2397
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R-2397 SERVICE MANUAL PRODUCT SPECIFICATIONS COMMERCIAL GENERAL INFORMATION R-2397 GENERAL IMPORTANT INFORMATION APPEARANCE VIEW This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information. It is recommended that service engineers carefully study the OPERATING SEQUENCE entire text of this manual, so they will be qualified to render satisfactory customer service. CAUTION FUNCTION OF IMPORTANT MICROWAVE RADIATION COMPONENTS DO NOT BECOME EXPOSED TO
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R-2397 PRODUCT DESCRIPTION SPECIFICATION ITEM DESCRIPTION Power Requirements 230 Volts 50 Hertz Single phase, 3 wire grounded Power Consumption 2.7 kW Approx. 13A Power Output 1700 watts nominal of RF microwave energy (Method of IEC 705) Operating frequency of 2450MHz Outside Dimensions Width 510mm Height 335 mm Depth 470 mm Cooking Cavity Dimensions Width 330 mm Height 180 mm Depth 330 mm Control Complement Touch Control System The combination of cooking time and microwave power The oven can be
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R-2397 APPEARANCE VIEW OVEN 11 10 5 4 3 2 1. Control panel 19 14 18 2. Hole for safety door latches 3. Ceramic floor 1 4. Splash cover 13 15 5. Oven light 8 6. Air intake filter 16 7. Air intake openings 12 8. Oven cavity 9 6 17 7 9. Door seals and sealing surfaces 10. Door hinges 11. Oven door with see-through window AUTO TOUCH CONTROL PANEL 12. Door safety latches 13. Door handle. 34 14. Outer cabinet 6 DISPLAY AND INDICATORS 15. Removable cover over oven light bulb DEF CHECK NUMBER Check indi
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R-2397 OPERATION SEQUENCE OFF CONDITION the relay RY1 stays closed. Shown in the display is the remaining time, but the program is cancelled if the oven Closing the door activates all door interlock switches is not started within 3 minutes. (1st latch switch, 2nd latch switch, 3rd latch switch and stop switch) 6. MONITOR SWITCH CIRCUIT The monitor switch is mechanically controlled by oven IMPORTANT door, and monitors the operation of the 1st latch switch. When the oven door is closed, the monito
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C1: H.V. CAPACITOR ASYMMETRIC
RECTIFIER C2: H.V. CAPACITOR ASYMMETRIC
RECTIFIER R-2397 T2: HIGH VOLTAGE
T1: HIGH VOLTAGE
TRANSFORMER TRANSFORMER (FRONT) (REAR) COMMERCIAL FREQUENCY (50HZ) POWER OUTPUT BY MAGNETRON 1 OPERATION OF MAGNETRON H. V. RECTIFIER H. V. RECTIFIER POWER OUTPUT BY MAGNETRON 2 MG2: MAGNETRON (LOWER) MG1: MAGNETRON (UPPER) Figure B-1. High Voltage Circuit Figure B-2. Operation of Magnetron FUNCTION OF IMPORTANT COMPONENTS MONITOR SWITCH DOOR OPEN MECHANISM The
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R-2397 FUSE F6.3A 250V MAGNETRON THERMISTOR 1. If the wire harness or electrical components are short- The air temperature around the lower magnetron is circuited, this fuse blows to prevent an electric shock detected through the resistance of the thermistor. or fire hazard. If the temperature is high, the control panel will display 2. The fuse also blows when 1st latch switch remains "EE17" and the oven will stop to protect the lower closed with the oven door open and when the monitor magnetron
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R-2397 SERVICING WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will result in electrocution. High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage harness. REMEMBER TO CHECK 3D REMEMBER TO CHECK 4R 1) Disconnect the supply. 1) Reconnect all leads removed from components 2) Door opened, and wedged open. during testing. 3) Discharge high voltage ca
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R-2397 TEST PROCEDURE A A B B CCCD D E E E E E F F G H POSSIBLE CAUSE AND DEFECTIVE PARTS PPROBLEM CONDITION “ . “ does not appear on display when power cord is plugged into wall outlet. Control panel can not accept key in. Fuse F6.3A blows when the door is opened. Home fuse blowns when power cord is plugged into wall outlet. Weak point A017 blowns when power cord is plugged into wall outlet. Oven lamp, fan motor and stirrer motors do not work for 1 minute whenever the door is opened OFF or af
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R-2397 II I I J L K K K L M N P Q O 9 MAGNETRON THERMAL CUT-OUT 145˚C TC1 MAGNETRON THERMAL CUT-OUT 145˚C TC2 B. MOTOR THERMAL CUT-OUT 115˚C TC3 OVEN THERMAL CUT-OUTT 115˚C TC4 MONITOR RESISTOR R1 STIRRER MOTOR MAGNETRON THERMISTOR EXHAUST THERMISTOR INTAKE THERMISTOR OVEN LAMP OR SOCKET BLOWER MOTOR NOISE FILTER POWER SUPPLY CORD FUSE HOLDER SHORTED WIRE HARNESS OPENED WIRE HARNESS TOUCH CONTROL PANEL RELAY RY-1, RY-3, RY-4 FOIL PATTERN BLOCKED VENTILATION OPENINGS BLOCKED BLOWER MOTOR MIS ADJU
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER A MAGNETRON TEST NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION. CARRY OUT 3D CHECK. Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal. To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a reading of less than 1 ohm. To test for short filament to
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Initial temperature............................................................................................... T1 = 11°C Temperature after (25 + 3) = 28 sec. ................................................................. T2 = 21°C Temperature difference Cold-Warm ................................................................... ΔT = 10°C Measured output power The equation is “P = 170 x ΔT” ...........................................
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric rectifier can be tested using an ohmmeter set to its highest range. Contact the ohmmeter across the terminals A+B of the asymmetric rectifier and note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is indicated in both directions then the asymmetric rectifier is good. If an asymmetric rectifier is shorted in either
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER G WEAK POINT A017 CARRY OUT 3D CHECKS. If the weak point A017 is blown, there could be a shorts or grounds in electrical parts or wire harness. Check them and replace the defective parts or repair the wire harness. CARRY OUT 4R CHECKS. CAUTION: Only replace weak point A017 with the correct value replacement. H FUSE F6.3A TEST CARRY OUT 3D CHECKS. If the fuse F6.3A is blown when the door is opened, check the latch switch, monitor switch and m
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER K MAGNETRON THERMISTOR TEST CARRY OUT 3D CHECKS. Disconnect connector-H from the CPU unit. Measure the resistance of the thermistor with an ohmmeter. Connect the ohmmeter leads to the leads of the thermistor. Room Temp. Resistance 15˚C ........................ Approx. 15.91 kΩ 20˚C ........................ Approx. 13.04 kΩ 25˚C ........................ Approx. 10.74 kΩ If the meter does not indicate above resistance, replace the thermistor.
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R-2397 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER WHT N L F1 L (min) Cx ± 20% Cy ± 20% Cx 0.5mH 0.22 μF 4700 pF L L Cy BLK MEASURING POINT INDICATION OF OHMMETER Between N and L Open circuit Between terminal N and WHITW Short circuit Between terminal L and BLK Short circuit If incorrect readings are absorbed, replace the noise filter. CARRY OUT 4R CHECKS. N TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LSI, IC, etc. Therefore
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R-2397 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER If a specific pad does not respond, the above method may be used (after clearing the control unit) to determine if the control unit or key pad is at fault. P RELAY TEST CARRY OUT 3D CHECKS. Remove the outer case and check voltage between Pin Nos. 5 and 7 of the connector (A) on the control unit with an A.C. voltmeter. The meter should indicate 230 volts, if not check control unit circuity. RY1, RY3 and RY4 Relay Test These relays
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R-2397 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units as This AC voltage is then half wave rectified by D61/D62 shown in the touch control panel circuit. and smoothed (filtered) by C61/C62. This AC voltage is the input to the IN3 and IN5 ports of (1) Control Unit IC1, which determines if there is a magnetron / high (2) Key Unit voltage problem. The principal functions of these units and the signals commu- nicated among them a
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R-2397 DESCRIPTION OF LSI LSI(IZA646DR) The I/O signal of the LSI(IZA646DR) is detailed in the following table. Pin No. Signal I/O Description 1 VREF IN Reference voltage input terminal. A reference voltage applied to the A/D converter in the LSI. Connected to GND.(0V) 2 IN7 IN Temperature measurement input: MAGNETRON THERMISTOR. By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into temperature by the A/D converter built into the LSI. 3
