R-27STM SERVICE MANUAL No. S0801R27STPKS STIR TURN KG PCS MICROWAVE OVEN MODEL R-27STM In interests of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used.
R-27STM BEFORE SERVICING GENERAL IMPORTANT INFORMATION 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 entire text of this manual, so they will be qualified to render satisfactory customer service.
R-27STM WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part of the high voltage circuit will result in electrocution. High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage fuse, High voltage harness. REMEMBER TO CHECK 3D REMEMBER TO CHECK 4R Disconnect the supply. Door opened, and wedged open. Reconnect all leads removed from components during testing.
R-27STM PRODUCT SPECIFICATIONS ITEM DESCRIPTION Power Requirements 230 - 240 Volts 50 Hertz Single phase, 3 wire earthed Power Consumption 1.
R-27STM TOUCH CONTROL PANEL 1. DIGITAL DISPLAY 1 2. INDICATORS STIR TURN KG PCS MICRO COOK 2 BUTTONS: 3. AUTO COOK 3 4. EXPRESS COOK 5. EXPRESS DEFROST 6. START/AUTO MINUTE 7. STOP/CLEAR 4 8. POWER LEVEL 9. TIME/WEIGHT KNOB 5 NOTE: Some one-touch cooking features such as "START/AUTO MINUTE" are disabled after three minutes when the oven is not in use. These features are automatically enabled when the door is opened and closed or the STOP button is pressed.
R-27STM NOTE: The ON/OFF time ratio does not exactly correspond to the percentage of microwave power, because approx. 3 seconds are needed for heating up the magnetron filament. MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING When the microwave oven is preset for variable cooking power, rated voltage is supplied to the high voltage transformer inter mittently within a 32 second time base through the relay contact which is coupled with the current-limiting relay (RY2).
R-27STM TROUBLESHOOTING GUIDE FOREWORD IMPORTANT: 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. If the oven becomes inoperative because of a blown fuse T6.3A in the 1st. latch switch - relay (RY1) - 2nd.
R-27STM TEST PROCEDURES A: MAGNETRON TEST NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION. 111 CARRY OUT 3D CHECKS. 222 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. 333 To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground.
R-27STM 444 CARRY OUT 4R CHECKS. C: HIGH VOLTAGE RECTIFIER TEST CARRY OUT 3D CHECKS. Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal of the high voltage rectifier and note the reading obtained. Reverse the me ter leads and note this second reading. The normal resistance is infinite in one direction and more than 100 kW in the other direction. CARRY OUT 4R CHECKS.
R-27STM H: FUSE T6.3A CARRY OUT 3D CHECKS. If the fuse T6.3A is blown when the door is opened, check the 1st. latch switch, relay (RY1), 2nd. interlock relay (RY2) and monitor switch. If the fuse T6.3A is blown by incorrect door switching replace the defective switch(es) and the fuse T6.3A. If the fuse T6.3A is blown, there is 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 FUSE T6.
R-27STM L: SWITCH UNIT TEST 111 CARRY OUT 3D CHECKS. 222 Isolate the switch unit with the control panel frame to be tested. 333 Using an ohmmeter and referring to the switch unit matrix indicated on the switch unit circuit, check the circuit between the pins of the switch unit that correspond to the STOP button. When the button is pressed, the ohmmeter should indicate short circuit. When the button is released, the ohmmeter should indicate open circuit.
R-27STM TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units as shown in the touch control panel circuit. (1) Switch Unit (2) Control Unit The principal functions of these units and their related signals are explained below. Switch Unit The switch unit is composed of a matrix, signals generated in the LSI are sent to the switch unit through P22, P24, P25 and P26.
R-27STM 2) Servicing the touch control panel with power supply from an external power source: (4) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape. Disconnect the touch control panel completely from the oven proper, and short both ends of the door sensing switch (on PWB) of the touch control panel, which brings about an operational state that is equivalent to the oven door being closed.
R-27STM 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 se vere, possibly fatal, electric shock. (Example) High Voltage Capacitor, High Voltage Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage fuse, High Voltage Harness etc.. possible exposure to microwave energy.
R-27STM HIGH VOLTAGE TRANSFORMER REMOVAL from high voltage capacitor. 111 CARRY OUT 3D CHECKS. 222 Disconnect the wire leads (main wire harness and H. V. fuse) from high voltage transformer. 555 Remove the two (2) screws holding the transformer to bot tom plate from below. 333 Disconnect the filament lead of high voltage transformer from the magnetron. 666 Remove the two (2) screws holding the transformer to bot tom plate from above.
R-27STM 555 Re-install the turntable motor cover to the bottom plate with one (1) screw. 666 Remove one (1) screw holding turntable motor to oven cav ity. 777 Remove the TTM packing from the turntable motor. TTM packing 888 Now, the turntable motor is free. REINSTALL 111 Re-install the TTM packing to the turntable motor. 222 Re-install the turntable motor with the TTM packing with the single (1) screw to the oven cavity bottom plate.
R-27STM Power Supply Cord Screw Oven Cavity Back Plate P ower S upply C ord Moulding C ord S topper Brown Wire RED Green/Yellow Wire WHT L Oven C avity B ack P late N Blue Wire S quare Hole Noise Filter Figure C-3(a) Power Supply Cord Replacement Figure C-3(b) Power Supply Cord Replacement CONTROL PANEL ASSEMBLY REMOVAL 333 Lift up the control panel assembly and release it from the oven cavity. CARRY OUT 3D CHECKS. 111 Disconnect the leads from the control unit.
R-27STM DOOR REPLACEMENT 666 Catch two (2) pins of door panel on two (2) hole of upper and lower oven hinges REMOVAL 111 Disconnect the power supply cord. 777 Re-install choke cover to door panel by pushing. 222 Open the door slightly. NOTE: After any service to the door; 333 Insert a putty knife (thickness of about 0.5mm) into the gap between the choke cover and corner portion of door panel as shown in Figure C-6 to free engaging parts. Make sure that 1st. latch switch, 2nd.
R-27STM MICROWAVE MEASUREMENT After any repair, the microwave oven must be checked for microwave leakage to ensure continued safe operation. BS EN 60335-2-25 specifies that the maximum permitted leakage with a load of 275 ml is 50 W/m2 (equivalent to 5 mW/cm2) at a distance of 5 cm from the oven.
R-27STM CIRCUIT DIAGRAMS Oven Schematic SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. NOTE: " TEMP. FUSE HIGH VOLTAGE TRANSFORMER FUSE T6.3A BRN H.V. FUSE 0.6A FM H.V. RECTIFIER B1 MONITOR SWITCH B2 FAN MOTOR CONTROL UNIT TURNTABLE MOTOR (RY-1) OVEN LAMP OL (RY-2) TTM 2ND. INTERLOCK RELAY NOISE SUPPRESSION COIL G-Y LIVE NEUTRAL EARTH 50Hz 230 - 240V BLU MAGNETRON L NOISE FILTER " indicates components with potentials above 250V N 2ND. INTERLOCK RELAY CONTROL SWITCH 1ST.
WH-B WH-A (SWITCH UNIT) GRY GRY WHT RY1 1 2 R E D B L K T1 RED ORG RY2 CN-B CN-H CN-G (POWER UNIT) CONTROL PANEL BLK COM 1ST. LATCH SWITCH N.O. COMN.O. GRN GRY GRY GRY GRY COM BLU N.C. COM N.O. 2ND.
R-27STM Control Unit Circuit Figure S-2. Control Unit Circuit 22 R27STM.
R-27STM Printed Wiring Board LD1 LD2 LD3 LD4 DIP 10 CN-G IC SIDE C6 R3 + D5 B - Q2 (JUMP A) E JUMP1 R2 CN-H SP1 D6 ZD1 B Q22 E B JUMP2 ZD2 C12 R1 D22 + E C5 + ZD3 C21 - JUMP3 D40 2 1 CN-B JUMP4 1 - C1 R21 B E Q23 Q21 R22 D2 D1 D3 D4 R20 D20 T1 P VRS1 RY1 S d (J1) a b D21 c RY2 Figure S-3. Printed Wiring Board of Power Unit Figure S-4. Printed Wiring Board of Switchr Unit 23 R27STM.
R-27STM PARTS LIST NOTE: Parts marked "*" may cause undue microwave exposure. Parts marked "∆" are used in voltage more than 250V. REF. NO.
R-27STM REF. NO.
R-27STM 7-8 7-9 2-1 7-8 7-8 7-9 4-6 7-8 7-6 7-8 1-9 7-8 4-9 7-1 1-13 4-11 7-8 1-1 1-5 7-1 7-8 7-6 1-3 7-7 4-4 4-5 7-6 7-2 4-7 4-13 7-7 4-8 7-10 1-8 7-1 6-1 4-3 7-4 4-16 4-1 4-10 1-10 1-11 7-1 4-12 1-7 1-14 7-8 4-14 7-3 1-10 6-2 4-2 1-12 1-2 2-2 1-4 7-1 1-6 7-8 2-3 7-9 7-8 7-7 7-9 7-8 4-15 7-8 2-3 26 R27STM.
R-27STM 5-11 5-10 5-1 5-2 5-13 5-12 5-9 5-8 5-6 3-9 5-14 3-10 5-12 5-3 3-10 5-7 3-1 3-10 3-2 3-11 3-5 3-6 5-5 5-4 3-10 6-4 3-7 3-3 6-5 3-8 3-4 6-6 27 R 27S T M.
R-27STM TOP PAD ASSEMBLY FPADBA713WRKZ POLYETHYLENG BAG SSAKHA014WRE0 DOOR PROTECTION SHEET SPADPA580WRE0 6-4 INSTRUCTION BOOK 6-1 TURNTABLE TRAY MICROWAVE OVEN AC CORD PAD SPADBA371WRE0 BOTTOM PAD ASSEMBLY FPADBA714WRKZ INTO THE OVEN CAVITY 6-2 TURNTABLE SUPPORT TRAY PAD ASSY (CPADBA287WRKZ) Not replaceable items. PACKING CASE SPAKCE720WREZ COPYRIGHT© 2008 BY SHARP CORPORATION ALL RIGHTS RESERVED.
