Sharp R-520LW, R-520LK service manual Figure of all digits flicker, KEY Unit Test

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R - 5 2 0 L K

R-520LW

TEST PROCEDURES

PROCEDURE

COMPONENT TEST

LETTER

 

2.

Control Unit

 

The following symptoms indicate a defective control unit.

2-1

In connection with pads.

 

a) When touching the pads, a certain group of pads do not produce a signal.

 

b) When touching the pads, no pads produce a signal.

2-2

In connection with indicators

 

a) At a certain digit, all or some segments do not light up.

 

b) At a certain digit, brightness is low.

 

c) Only one indicator does not light.

 

d) The corresponding segments of all digits do not light up; or they continue to light up.

 

e) Wrong figure appears.

 

f) A certain group of indicators do not light up.

 

g) The figure of all digits flicker.

2-3

Other possible problems caused by defective control unit.

a)Buzzer does not sound or continues to sound.

b)Clock does not operate properly.

c)Cooking is not possible.

3.If the Key unit or the Control unit is defective.

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)Replace the Control unit assembly.

5)Reconnect all leads removed from components during testing.

6)Re-install the outer case (cabinet).

7)Reconnect the power supply cord after the outer case is installed.

8)Run the oven and check all functions.

4.When 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 all leads removed from components during testing.

5)Re-install the outer case (cabinet).

6)Reconnect the power supply cord after the outer case is installed.

7)Run the oven and check all functions.

IKEY UNIT TEST

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.Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the circuit between the pins of the key unit that correspond to the STOP/CLEAR pad. When the pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and must be replaced. About the other pads, the above method may be used.

5.Reconnect all leads removed from components during testing.

6.Re-install the outer case (cabinet).

7.Reconnect the power supply cord after the outer case is installed.

8.Run the oven and check all functions.

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Contents Table of Contents 520LWBefore Servicing When the testing is completed Dont Touch Before ServicingMicrowave Measurement Procedure RequirementsLeakage test 520LK/R-520LW Sharp PLAZA, MahwahMicrowave Ovens ForewordDescription SpecificationGeneral Information Grounding InstructionsOven Diagram Touch Control PanelDescription of Operating Sequence Power Level P-0 to P-90 CookingOperation OFF ConditionSensor Cooking Condition MicrowaveSchematic Clock Appears on DisplayDescription and Function of Components Troubleshooting Guide Problem Test ProceduresTest Procedure Procedure Component Test Letter Magnetron Assembly TestProcedure Component Test Letter Microwave Output PowerPower Transformer Test Magnetron Temperature Fuse Test Procedure Component Test Letter High Voltage Rectifier TestCavity Temperature Fuse Test High Voltage Capacitor TestRun the oven and check all functions Replace Temperature FusePrimary Interlock Switch Test Secondary Interlock System TestProcedure Component Test Letter Monitor Switch Test Touch Control Panel Assembly TestFigure of all digits flicker KEY Unit TestRelay Test Compu Defrost TestMenu 1ST Stage 2ND Stage 3RD Stage STEAKS/CHOPS Level Time Primary on the PWB, this foil pattern acts as a fuse Steps Occurrence Cause or CorrectionTesting Method for AH Sensor AND/OR Control Unit AH Sensor TestChecking the initial sensor cooking condition Checking Control Unit R1, R2 22Ω ± 1% 1/2W R3 4.3Ω ± 5% 1/4W R4 1MΩ ± 5% 1/4WSensor Dummy Resistor Circuit Power Source Circuit Reset CircuitIndicator Circuit Synchronizing Signal CircuitDescription of LSI LSIPower source voltage Signal similar to ANI3Internal clock oscillation frequency control input setting Key strobe signalConverter power source voltage GND0V Converter power source voltageCommon data signal Operational Principle of Absolute Humidity Sensor Absolute Humidity Sensor CircuitStructure of Absolute Humidity Sensor Detector Circuit of Absolute Humidity Sensor CircuitServicing of Touch Control Panel Other PrecautionsTouch Control Panel Servicing Servicing ToolsComponent Replacement and Adjustment Procedure Outer Case RemovalTo prevent an electric shock, take the following pre High Voltage Rectifier and High Voltage Capacitor Removal Power Transformer RemovalRe-install Magnetron RemovalGraphic Sheet and Membrane Switch Replacement Positive Lock Connector NO-CASE Type RemovalControl Panel Assembly Removal Oven Lamp and Lamp Socket RemovalInstallation Turntable Motor RemovalRemoval InstallationCooling FAN Motor Removal Rear ViewDoor Replacement After adjustment, check the followingRE-INSTALL After any service, make sure of the followingSealer Film Diagram High Voltage ComponentsCircuit Control Unit Figure S-5 . Printed Wiring Board of Power Unit Parts List SCREWS,NUTS and Washers HOW to Order Replacement PartsMiscellaneous Model NumberOven and Cabinet Parts Control Panel Parts Door Parts Miscellaneous Packing and Accessories Copyright 2006 by Sharp Corporation ALL Rights Reserved

R-520LK, R-520LW specifications

The Sharp R-520LW and R-520LK are innovative microwave ovens that combine advanced technology with user-friendly features to enhance cooking experiences. Designed with modern kitchens in mind, these models embody efficiency, precision, and versatility.

One of the defining characteristics of both the R-520LW and R-520LK is their powerful 900-watt output, which allows for speedy cooking and reheating. This high wattage ensures that food is cooked evenly and retains its moisture, preventing the common issue of dry or unevenly heated meals. Furthermore, the inclusion of multiple cooking power levels provides users with flexibility, making it easy to select the ideal setting for various types of food.

Both models feature Sharp's signature Inverter Technology. Unlike traditional microwaves that use a turn-on and turn-off cycling method, inverter technology delivers a steady stream of cooking power. This results in more consistent heating, allowing delicate foods such as fish or custards to be cooked perfectly without overcooking the edges. This technology not only enhances the quality of cooked food but also improves the overall efficiency of the microwave.

The R-520LW and R-520LK come equipped with a variety of auto-cook settings that cater to different culinary needs. From popcorn to frozen vegetables, these pre-programmed settings allow users to prepare meals with just a touch of a button, making cooking uncomplicated for all skill levels. The large, user-friendly control panel features intuitive buttons and a digital display, ensuring effortless operation and visibility.

In terms of design, the R-520LW boasts a sleek white finish, while the R-520LK offers a modern black aesthetic. Both models are compact yet spacious, with a generous interior capacity that can accommodate a range of dish sizes. The turntable feature further enhances cooking efficiency by ensuring even cooking all around.

Cleaning and maintaining the R-520LW and R-520LK is a breeze, thanks to their easy-to-wipe surfaces and the interior's cavity that can be easily accessed. The durable construction of these microwaves means they are designed to withstand the rigors of daily use.

In summary, the Sharp R-520LW and R-520LK microwave ovens stand out with their advanced features, such as inverter technology and pre-programmed cooking settings, making them excellent choices for anyone looking to streamline their kitchen tasks. Their stylish designs and user-friendly interfaces further enhance their appeal, making them valuable additions to any modern home.
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