Sharp R-520LK, R-520LW service manual Description and Function of Components

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R - 5 2 0 L K

R-520LW

DESCRIPTION AND FUNCTION OF COMPONENTS

DOOR OPEN MECHANISM

The door is opened by pushing the open button on the con- trol panel, refer to the Figure D-1. When the open button is pushed, the open button pushes up the switch lever, and then the switch lever pushes up the latch head. The latch heads are moved upward and released from latch hook. Now the door will open.

 

Latch Heads

Door

Door S ensing

S witch

 

 

Monitor S witch

S witch Lever

 

 

P rimary Interlock

 

S witch

Figure D-1. Door Open Mechanism

DOOR SENSING AND PRIMARY INTERLOCK SWITCHES

The primary interlock switch is mounted in the lower position of the latch hook and the door sensing switch in the second- ary interlock system is mounted in the upper position of the latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the power to all high voltage components. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches. The secondary interlock system consists of the door sensing switch and secondary interlock relay located on the control circuit board.

MONITOR SWITCH

The monitor switch is activated (the contacts opened) by the latch head on the door while the door is closed. The switch is intended to render the oven inoperative, by means of blowing the monitor fuse, when the contacts of the second- ary interlock relay (RY2) and primary interlock switch fail to open when the door is opened.

Functions:

1.When the door is opened, the monitor switch contact close (to the ON condition) due to their being normally closed. At this time the secondary interlock relay (RY2) and primary interlock switch are in the OFF condition (contacts open) due to their being normally open contact switches.

2.As the door goes to a closed position, the monitor switch contacts are first opened and then the door sensing switch and the primary interlock switch contacts close. (On opening the door, each of these switches operate inversely.)

3.If the door is opened, and the secondary interlock relay (RY2) and primary 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, SECONDARY INTERLOCK RELAY (RY2), RE- LAY (RY1), PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").

NOTE: MONITOR FUSE AND MONITOR SWITCH ARE REPLACED AS AN ASSEMBLY.

TURNTABLE MOTOR

The turntable motor rotates the turntable located on the bottom of the oven cavity, so that the foods on the turntable cook evenly during cooking.The turntable may turn in either direction.

COOLING FAN MOTOR

The cooling fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes sur- rounding the magnetron and cools the magnetron. This air is channeled through the oven cavity to remove steam and vapors given off from the heating foods. It is then exhausted through the exhausting air vents at the oven cavity.

Cavity temperature fuse

The cavity temperature fuse located on the top of the oven cavity, is designed to prevent damage to the oven by fire. If the food load is overcooked, by either error in cook time or defect in the control unit, the cavity temperature fuse will open.

Under normal operation, the cavity temperature fuse remains closed. However, when abnormally high temperatures are reached within the oven cavity, the cavity temperature fuse will open at 302OF(150OC) causing the oven to shut down. NOTE: This is a fuse. It does not reset.

MONITOR FUSE

1.The monitor fuse blows when the contacts (COM-NO) of the primary interlock relay (RY2) and secondary interlock switch remain closed with the oven door open and when the monitor switch closes.

2.If the wire harness or electrical components are short- circuited, this monitor fuse blows to prevent an electric shock or fire hazard.

Magnetron temperature fuse

The magnetron temperature fuse located near the magne- tron is designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc.

Under normal operation, the magnetron temperature fuse

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Contents 520LW Table of ContentsBefore Servicing Dont Touch Before Servicing When the testing is completedLeakage test Microwave Measurement ProcedureRequirements Foreword Sharp PLAZA, MahwahMicrowave Ovens 520LK/R-520LWGrounding Instructions SpecificationGeneral Information DescriptionTouch Control Panel Oven DiagramOFF Condition Power Level P-0 to P-90 CookingOperation Description of Operating SequenceMicrowave Sensor Cooking ConditionClock Appears on Display SchematicDescription and Function of Components Troubleshooting Guide Procedure Component Test Letter Magnetron Assembly Test Test ProceduresTest Procedure ProblemPower Transformer Test Procedure Component Test LetterMicrowave Output Power High Voltage Capacitor Test Procedure Component Test Letter High Voltage Rectifier TestCavity Temperature Fuse Test Magnetron Temperature Fuse TestSecondary Interlock System Test Replace Temperature FusePrimary Interlock Switch Test Run the oven and check all functionsTouch Control Panel Assembly Test Procedure Component Test Letter Monitor Switch TestKEY Unit Test Figure of all digits flickerMenu 1ST Stage 2ND Stage 3RD Stage STEAKS/CHOPS Level Time Relay TestCompu Defrost Test Steps Occurrence Cause or Correction Primary on the PWB, this foil pattern acts as a fuseChecking the initial sensor cooking condition Testing Method for AH Sensor AND/OR Control UnitAH Sensor Test Sensor Dummy Resistor Circuit Checking Control UnitR1, R2 22Ω ± 1% 1/2W R3 4.3Ω ± 5% 1/4W R4 1MΩ ± 5% 1/4W Synchronizing Signal Circuit Reset CircuitIndicator Circuit Power Source CircuitLSI Description of LSIKey strobe signal Signal similar to ANI3Internal clock oscillation frequency control input setting Power source voltageCommon data signal Converter power source voltage GND0VConverter power source voltage Detector Circuit of Absolute Humidity Sensor Circuit Absolute Humidity Sensor CircuitStructure of Absolute Humidity Sensor Operational Principle of Absolute Humidity SensorServicing Tools Other PrecautionsTouch Control Panel Servicing Servicing of Touch Control PanelTo prevent an electric shock, take the following pre Component Replacement and Adjustment ProcedureOuter Case Removal Magnetron Removal Power Transformer RemovalRe-install High Voltage Rectifier and High Voltage Capacitor RemovalOven Lamp and Lamp Socket Removal Positive Lock Connector NO-CASE Type RemovalControl Panel Assembly Removal Graphic Sheet and Membrane Switch ReplacementTurntable Motor Removal InstallationRear View InstallationCooling FAN Motor Removal RemovalAfter adjustment, check the following Door ReplacementSealer Film RE-INSTALLAfter any service, make sure of the following High Voltage Components DiagramCircuit Control Unit Figure S-5 . Printed Wiring Board of Power Unit Parts List Model Number HOW to Order Replacement PartsMiscellaneous SCREWS,NUTS and WashersOven 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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