Sharp R-520LK, R-520LW TROUBLESHOOTING GUIDE

12

R-520LK

R-520LW

TROUBLESHOOTING GUIDE

Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is con-

nected.

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.

IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY1)

secondary interlock relay (RY2), door sensing switch and primary interlock switch before replacing the moni-

tor fuse. If the monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA016/KIT

as an assembly.

IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases,

be necessary to connect the power supply cord after the outer case has been removed, in this event:

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that the leads remain isolated from other components and oven chassis by using insulation

tape.

6. After that procedure, reconnect the power supply cord.

When the testing is completed

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Reconnect the leads to the primary of the power transformer.

5. Reinstall the outer case (cabinet).

Contents

Main TABLE OF CONTENTS R-520LK R-520LW MICROWAVE OVEN MODELS Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135 SERVICE MANUAL SHARP ELECTRONCS CORPORATION BEFORE SERVICING WARNING TO SERVICE PERSONNEL Before Servicing After repairing Don't Touch ! Danger High Voltage MICROWAVE MEASUREMENT PROCEDURE SHARP PLAZA, MAHWAH, NEW JERSEY 07430-2135 SERVICE MANUAL DANGER GENERAL INFORMATION GROUNDING INSTRUCTIONS SPECIFICATION ITEM DESCRIPTION OVEN DIAGRAM 3-Pronged Plug Grounded Receptacle Box Grounding Pin 3-Pronged Receptacle OPERATION DESCRIPTION OF OPERATING SEQUENCE OFF CONDITION COOKING CONDITION POWER LEVEL P-0 TO P-90 COOKING SENSOR COOKING CONDITION Cooking Sequence. Figure O-2 Oven Schematic - Cooking Condition Figure O-1 Oven Schematic - Off Condition GRY WHT GRY DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM DOOR SENSING AND PRIMARY INTERLOCK SWITCHES MONITOR SWITCH TURNTABLE MOTOR TROUBLESHOOTING GUIDE CK = Check / RE = Replace CK CK CK I CK Page Page Page Page Page Page a b c d Page Page TOUCH CONTROL PANEL ASSEMBLY DESCRIPTION OF LSI Page Page ABSOLUTE HUMIDITY SENSOR CIRCUIT TOUCH CONTROL PANEL SERVICING WARNING AGAINST HIGH VOLTAGE: OUTER CASE REMOVAL COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING FOR WIRING POWER TRANSFORMER REMOVAL HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL MAGNETRON REMOVAL Special screw Screw Driver (Type: TORX T20 H or GTXH20-100) POSITIVE LOCK CONNECTOR (NO-CASE TYPE) REMOVAL OVEN LAMP AND LAMP SOCKET REMOVAL CONTROL PANEL ASSEMBLY REMOVAL GRAPHIC SHEET AND MEMBRANE SWITCH REPLACEMENT TURNTABLE MOTOR REMOVAL COOLING FAN MOTOR REMOVAL DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL Side View Rear View DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT DOOR REPLACEMENT SEALER FILM 6 4 5 123 Figure S-1. Pictorial Diagram CN-F 3 2 BLK AHSENSOR Figure S-3. Control Unit Circuit Figure S-5 . Printed Wiring Board of Power Unit CN-B T1 C2 CN-F 1 2 3 PARTS LIST * ELECTRIC PARTS CABINET PARTS CONTROL PANEL PARTS HOW TO ORDER REPLACEMENT PARTS MISCELLANEOUS SCREWS,NUTS AND WASHERS OVEN AND CABINET PARTS 7-8 CONTROL PANEL PARTS DOOR PARTS MISCELLANEOUS 3-8 3-9 3-3 3-11 PACKING AND ACCESSORIES NCAVITY s tem i