R-300BW SERVICE MANUAL S5811R300BPW/ MICROWAVE OVEN MODEL R-300BW COOKING CONTROL DEFROST MED MED LOW MED HIGH LOW HIGH L ight U p Dial 1 2 30 25 3 4 0 20 15 14 5 6 7 8 9 10 11 13 12 In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used.
R-300BW 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.
R-300BW WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. Read the Service Manual carefully and follow all instructions. Don't Touch ! Danger High Voltage When the testing is completed, 1.
R-300BW MICROWAVE MEASUREMENT PROCEDURE A. Requirements: 1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven.
R-300BW SERVICE MANUAL PRODUCT DESCRIPTION MICROWAVE OVEN R-300BW GENERAL INFORMATION FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVEN, R-300BW. OPERATION It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service.
R-300BW SPECIFICATION ITEM DESCRIPTION Power Requirements 120 Volts / 12 Amperes 60 Hertz Single phase, 3 wire grounded Power Output 900 watts (IEC-705 TEST PROCEDURE) Operating frequency of 2450MHz Width 20-1/2" Height 11-7/8" Depth 15-7/8" Width 13-3/4" Height 8-3/8" Depth 14-7/8" Case Dimensions Cooking Cavity Dimensions 1.0 Cubic Feet Control Complement Light up dial timer (30 minutes) Microwave Power for Variable Cooking Repetition Rate; HIGH ....................................
R-300BW OVEN DIAGRAM 7 8 9 4 11 1 2 6 5 10 3 1. One touch door open button. Push to open door. 2. Door latches. The oven will not operate unless the door is securely closed. 3. Removable turntable support. 4. Removable turntable. The turntable will rotate clockwise or counterclockwise. 5. Oven lamp. It will light when oven is operating or door is opened. 6. Oven door with see-through window. 7. Ventilation openings. (Rear) 8. Control panel. 9. Coupling. 10. Wave guide cover. 11.
R-300BW OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during oven operation. (2) When the door is closed from the open position, the monitor switch contacts open first. Then the contacts of the secondary interlock switch and door sensing switch close. And contacts of the relay (RY1) open.
R-300BW SCHEMATIC NOTE: CONDITION OF OVEN 1. LIGHT UP DIAL OFF. 2. DOOR CLOSED. MONITOR FUSE 15A THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MG.) A3 COM. POWER TRANSFORMER N.O. (RY-2) (RY-1) A5 CAPACITOR 0.94µF AC 2000V PRIMARY INTERLOCK RELAY CONTROL UNIT A1 GRN B2 120V AC 60 Hz B1 DOOR SENSING SWITCH TTM OL MONITOR SWITCH FM RECTIFIER MAGNETRON OVEN LAMP TURNTABLE MOTOR FAN MOTOR SECONDARY INTERLOCK SWITCH Figure O-1.
R-300BW DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM (RY2) and secondary interlock switch contacts fail to open, the monitor fuse blows simultaneously with closing of the monitor switch contacts. CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE TEST THE DOOR SENSING SWITCH, PRIMARY INTERLOCK RELAY (RY2), SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE"). NOTE: MONITOR FUSE AND MONITOR SWITCH ARE REPLACED AS AN ASSEMBLY.
R-300BW TROUBLESHOOTING GUIDE Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected. When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the "Test Procedure "section.
R-300BW CK = Check / RE = Replace Home fuse or circuit breaker blows when power cord is plugged into wall receptacle OFF CONDITION Monitor fuse blows when power cord is plugged into wall receptacle. Oven lamp does not light when door is opened. Oven lamp does not go out when door is closed. Oven lamp lights but fan motor and turntable motor do not operate. COOKING CONDITION Oven does not go into cook cycle when Light Up Dial is turned.
R-300BW TEST PROCEDURES PROCEDURE LETTER A COMPONENT TEST MAGNETRON ASSEMBLY TEST 1. 2. 3. 4. 5. 6. 7. 8. 9. Disconnect the power supply cord, and then remove outer case. Open the door and block it open. Discharge high voltage capacitor. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than 1 ohm.
R-300BW TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.) C HIGH VOLTAGE RECTIFIER TEST 1. 2. 3. 4. Disconnect the power supply cord, and then remove outer case. Open the door and block it open. Discharge high voltage capacitor. Isolate the rectifier from the circuit.
R-300BW TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE THERMAL CUT-OUT. F SECONDARY INTERLOCK SWITCH TEST 1. 2. 3. 4. 5. 6. 7. 8. Disconnect the power supply cord, and then remove outer case.
R-300BW TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 5. 6. 7. 8. with the door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing the monitor switch, reconnect the wire lead to the monitor switch (COM) terminal and check the continuity of the monitor circuit. Reconnect all leads removed from components during testing. Reinstall the outer case (cabinet).
R-300BW TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST c) Only one LED does not light up. d) All or some LEDs continue to light up. e) A certain group of LEDs do not light up. f) The LEDs flicker. 1-2 Other possible troubles caused by defective control unit. a) Buzzer does not sound or continues to sound. b) Clock is not possible. c) Cooking time can not be set. d) Power level can not be set. When testing is completed, 1) Disconnect the power supply cord and then remove outer case.
R-300BW TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 2) Open the door and block it open. 3) Discharge high voltage capacitor. 4) Follow the troubleshooting guide given below for repair. STEPS 1 2 OCCURRENCE CAUSE OR CORRECTION Only pattern at "a" is broken. Pattern at "a" and "b" are broken. (J1) 5 d a 1 VRS1 P b CN - A S 5) Make a visual inspection of the varistor.
R-300BW CONTROL PANEL ASSEMBLY OUTLINE OF CONTROL PANEL 5) Buzzer Circuit The buzzer is responsive to signals from the LSI to emit audible sounds (key touch sound and completion sound). Control Unit Control unit consists of LSI, power source circuit, synchronizing signal circuit, ACL circuit, buzzer circuit, encoder circuit, indicator circuit and potentiometer circuit. 6) Door Sensing Switch (Stop Switch) A switch to "tell" the LSI if the door is open or closed.
R-300BW DESCRIPTION OF LSI LSI(IZA882DR) The I/O signal of the LSI(IZA882DR) are detailed in the following table. Pin No. Signal I/O Description 1 RST IN Auto clear terminal. Signal is input to reset the LSI to the initial state when power is applied. Temporarily set to "L" level the moment power is applied, at this time the LSI is reset. Thereafter set at "H" level. 2 INT IN Signal coming from encoder. When the encoder is turned, the contacts of encoder make pulse signals.
R-300BW Pin No. 23 Signal I/O D6 OUT Description ON/OFF time ratio in Micro cooking (a. 32second time base) Magnetron high-voltage circuit driving signal. To turn on and off the cook relay (RY2). In 100% POWER operation, the signals hold "L" level during microwave cooking and "H" level while not cooking. In other cooking modes (70%, 50%, 30%, 10%) the signal turns to "H" level and "L" level in repetition according to the power level.
R-300BW SERVICING 1. Precautions for Handling Electronic Components This unit uses CMOS LSI in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. CMOS LSI have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electricity charge in clothes, etc. and sometimes it is not fully protected by the built-in protection circuit.
R-300BW COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven. 1.
R-300BW CAUTION: 1. DISCONNECT OVEN FROM POWER SUP PLY BEFORE REMOVING OUTER CASE. 2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. NOTE: When replacing the outer case, the 2 special Torx screws must be reinstalled in the same locations. Special screw Screw Driver (Type: TORX T20 H or GTXH20-100) POWER TRANSFORMER REMOVAL 1. Disconnect the power supply cord and remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4.
R-300BW MAGNETRON REMOVAL Removal 1. Disconnect the power supply cord and remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect wire leads from magnetron. 5. Remove the one (1) screw holding chassis support to magnetron. 6. Remove the chassis support from oven. 7. Carefully remove the four (4) screws holding magnetron to waveguide flange. 8. Lift up magnetron with care so that magnetron antenna is not hit by any metal object around antenna. 9.
R-300BW TURNTABLE MOTOR REMOVAL 1. Disconnect the power supply cord. 2. Remove turntable and turntable support from oven cavity. 3. Lay the oven on it's backside. Remove the turntable motor cover by snipping off the material in four corners. 4. Where the corners have been snipped off bend corner areas flat. No sharp edges must be evident after removal of the turntable motor cover. 5. Disconnect wire leads from turntable motor. (See "Positive lock connector removal") 6.
R-300BW DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL Re-install 1. Re-install each switch in its place. The secondary interlock/monitor switches are in the lower position and the door sensing switch is in the upper position. 2. Re-connect wire leads to each switch. Refer to pictorial diagram. 3. Secure latch hook (with two (2) mounting screws) to oven flange. 4. Make sure that the monitor switch is operating properly and check continuity of the monitor circuit.
R-300BW Pin 9. Release door panel from seven (7) tabs of door frame by sliding door panel downward. 10.Now, door panel with sealer film is free. 11.Tear sealer film from door panel. 12.Now, door panel is free. 13.Slide latch head upward and remove it from door frame with releasing latch spring from door frame and latch head. 14.Now, latch head and latch spring are free. 15.Remove door screen from door frame by releasing two (2) tabs. 16.Now, door screen is free.
1 H 2 3 27 CN-B RY2 SP1 T1 BLK ORG RED RED N.C. F 4 COM. 5 COM. WHT GRY WHT WHT WHT BLK WHT BLK BLK WHT Figure S-1. Pictorial Diagram TURNTABLE MOTOR FAN MOTOR GRY BLK BLK GRY RED GRY H N POWER TRANSFORMER MAGNETRON HIGH VOLTAGE COMPONENTS NOTE: The neutral (WHT) wire must be connected to the terminal with "N" mark on the power supply cord.
(J1) b VRS1 R61 4.7k R60 4.
R-300BW 1 2 4 3 5 6 A A LD7 LD6 LD8 LD5 LD9 1 2 3 4 5 LD4 LD3 LD10 LD11 6 LD2 LD12 LD1 LD13 B B LD14 SW1 A B C LD15 R60 R61 LD16 LD18 LD24 LD17 7 LD23 LD22 LD21 C LD20 R63 C R54 R53 R52 10 R51 B Q52 E Q51 Q50 R50 E E E 9 Q53 11 8 LD19 C60 R62 R55 B B B C61 12 13 14 15 16 17 18 D D 19 20 21 22 23 24 25 26 27 28 29 ,F (JA) B B B Q23 D20 E CN - B Q22 1 37 B 38 R4 SP1 C21 B C20 D30 2 35 34 R30 R20 C4 E 36 Q40 E 33 D5 C5 R31 30 C30
R-300BW PARTS LIST Note: The parts marked “∆” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. REF. NO. PART NO.
R-300BW REF. NO. R62-63 RY1 RY2 SP1 SW1 T1 VR1 VRS1 ZD1 ZD2 3- 2 3- 3 3- 4 3- 5 3- 6 3- 7 3- 8 3- 9 3- 10 PART NO.
R-300BW HOW TO ORDER REPLACEMENT PARTS To have your order filled promptly and correctly, please furnish the following information. 1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION Order Parts from the authorized SHARP parts Distributor for your area. Defective parts requiring return should be returned as indicated in the Service Policy.
R-300BW 2 1 4 3 6 5 7-5 OVEN AND CABINET PARTS 2-1 7-8 A A 7-5 4-1 7-8 1-11 7-5 B B 1-10 4-9 7-1 7-3 1-4 7-7 7-2 4-10 6-7 C 6-11 6-11 1-13 C 1-8 6-6 4-17 4-16 1-5 D 7-4 D 6-10 7-6 7-3 4-7 4-15 E E 4-12 1-1 6-9 7-5 1-6 7-1 1-2 7-1 4-2 4-14 7-5 1-7 4-3 1-12 F 1-1 2-2 7-3 4-8 4-4 F 1-3 7-5 4-11 4-5 7-1 7-6 7-1 4-6 1-14 G 6-2 G 4-13 7-6 1-9 2-4 2-3 7-6 6-1 2-5 7-6 H 7-6 7-6 H 7-6 7-6 1 2 7-6 2-4 4 3 33 5 6
R-300BW 2 1 A 4 3 6 5 TOP PAD ASSEMBLY PACKING AND ACCESSORIES A FPADBA341WRK0 B B DOOR PROTECTION SHEET SPADPA204WRE0 PLASTIC BAG C C SSAKHA034WRE0 6- 8 INSTRUCTION BOOK & PRINTING MATTER D D 6- 2 TURNTABLE TRAY BOTTOM PAD ASSEMBLY E E FPADBA342WRK0 6- 1 TURNTABLE SUPPORT TRAY PACK INTO THE OVEN CAVITY F F SPADFA397WRE0 G G Not replaceable items. PACKING CASE SPAKCD105WRE0 H 1 2 4 3 5 H 6 COPYRIGHT © 1998 BY SHARP CORPORATION ALL RIGHTS RESERVED.