Sharp R-930AW service manual Troubleshooting Guide, Heating Element, Convection Cooking System

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R-930AK

R-930AW

HEATING ELEMENT

The heating element is located at the left side of the oven cavity. It is intended to heat air driven by the convection fan. The heated air is kept in the oven and force-circulated and reheated by the heating element.

CONVECTION COOKING SYSTEM

This oven is designed with a hot air heating system where food is not directly heated by the heating element, but is heated by forced circulation of the hot air produced by the heating element.

The air heated by the heating element is circulated through the convection passage provided on the outer casing of the oven cavity by means of the convection fan which is driven by the convection motor. It then enters the inside of the oven through the vent holes provided on the left side of the oven. Next, the hot air heats the food on the turntable and leaves the oven cavity through the vent in the center of the oven cavity left side wall.

Without leaving the oven, this hot air is reheated by the heating element, passes through the convection passage and enters the inside of the oven cavity again, in a continu- ing cycle.

In this way, the hot air circulates inside the oven cavity to raise its temperature and, at the same time, comes into contact with the food being cooked.

When the temperature inside the oven cavity reaches the selected temperature, the heating element is de-energized. When the temperature inside the oven cavity drops below the selected temperature, the heating element is energized again. In this way, the inside of the oven cavity is maintained at approximately the selected temperature.

When the convection time reaches 0, the heating element is de-energized and the convection fan stops operating and the oven shuts off.

DAMPER OPEN-CLOSE MECHANISM

Usually, the damper is in the open position except during convection cooking. Damper position is set automatically by damper motor, damper switch, motor cam and damper shaft. These components are operated by a signal that judges if microwave cooking or convection cooking opera- tion is selected by the control unit.

Microwave Cooking:

Damper is in the open position, because a portion of cooling air is channelled through the cavity to remove steam and vapors given off from the heating foods.

It is then exhausted at the top of the oven cavity into a condensation compartment.

Convection Cooking:

Damper is in the closed position, so that no hot air will be allowed to leak out the oven cavity.

Damper Operation

1.When power supply cord is plugged in:

1-1. When power supply cord is plugged in, a signal is sensed in the control unit, and operates shut-off relay (RY4).

1-2. Contacts of shut-off relay (RY4) close, the damper

motor is energized, opening the damper door.

1-3. When the damper is moved to the open position by the damper cam the damper switch is closed (ON position).

1-4. The signal from damper switch is re-sensed in the control unit and shut-off relay (RY4) is turned off.

1-5. The 120 volts A.C. to the damper motor is removed and the motor turns off.

2.When oven is microwave cooking: Damper is in the open position.

3.When oven is convection cooking:

3-1. Damper motor is energized by touching the convection, temperature and START pads.

3-2. When damper is in the closed position (damper switch is OFF), its signal is sensed by the control unit, and shut-off relay (RY4) is de-energized.

3-3. The damper is held in the closed position during the convection cooking operation.

3-4. At the end of the convection cooking, shut-off relay (RY4) is energized, and the damper is returned to the open position.

NOTE: If the damper door is not in the proper position, closed during convection or open during microwave, the control unit will stop oven operation after 1 minute.

DAMPER SHAFT

DAMPER DUCT

DAMPER

DAMPER CAM

DAMPER SWITCH

DAMPER MOTOR

Figure D-2. Damper Mechanism

TROUBLESHOOTING GUIDE

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, primary interlock relay, door sensing switch and secondary interlock switch before replacing the monitor fuse. If monitor fuse is replaced, the mintor switch must olso be replaced at the same time. Use part FFS-BA012WRK0 as an assembly.

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Contents Table of Contents Convection Microwave Oven930AK 930AW Before Servicing Leakage test Microwave Measurement ProcedureRequirements 930AK / R-930AW Sharp PLAZA, MahwahConvection Microwave Oven ForewordDescription SpecificationGeneral Information Grounding InstructionsOven Diagram Touch Control PanelDescription of Operating Sequence Power Level P-0 to P-90 CookingOperation OFF ConditionSensor Cooking Condition Convection Cooking ConditionAutomatic MIX Cooking Condition Preheating ConditionCompu Defrost Cooking Fire Sensing Feature Microwave ModeCompu BROIL/ Compu ROAST/ Compu Bake Cooking SequenceSchematic Diagram Figure O-1. Oven Schematic-OFF ConditionFigure O-4. Oven Schematic-Convection Cooking Condition Description and Function of Components Convection Cooking System Troubleshooting GuideHeating Element Damper OPEN-CLOSE MechanismTest Procedure Problem Possible Cause Defective PartsPower Transformer Test Test ProceduresProcedure Component Test Letter Magnetron Assembly Test High Voltage Rectifier TestMonitor Switch Procedure Component Test LetterSecondary Interlock Switch Test Temperature Fuse TestChecking Temperature in the Convection Mode Test Procedures Component Test LetterDamper Switch Test Thermal CUT-OUT TestKEY Unit Test Outer Case Switch TestTouch Control Panel Assembly Test Compu Defrost Test Weight 1ST Stage 2ND Stage 3RD Stage 4TH Stage Level TimeRelay Test Checking the initial sensor cooking condition Occurrence Cause or CorrectionAH Sensor Test Water load cooking testChecking Control Unit Test Procedures Letter Component TestTesting Method for AH Sensor AND/OR Control Unit R1,R2 22Ω ± R3 4.3kΩ ± 5% 1/4WTouch Control Panel Assembly ThermistorDescription of LSI LSIIZA797DRTOR Segment data signal Signal similar to P27Segment data signals Key strobe signalAbsolute Humidity Sensor Circuit Structure of Absolute Humidity SensorServicing Power Transformer Removal Component Replacement and Adjustment ProcedureOuter Case Switches Replacement Outer Case RemovalMagnetron Removal High Voltage Rectifier Assembly RemovalPositive Lock Connector NO-CASE Type Removal High Voltage Capacitor RemovalOven Lamp and Lamp Socket Removal Damper Assembly RemovalTurntable Motor Removal FAN Motor RemovalControl Panel Assembly and Control Unit Removal Control Unit and KEY UnitDoor Adjustment Door Replacement and AdjustmentAfter adjustment, check the following After adjustment, make sure of the followingDoor Disassembly Figure C-5. Door Replacement and adjustmentFigure S-1. Pictorial Diagram Circuit Control PanelDIP Control Panel Parts Electrical PartsCabinet Parts Oven Parts VSDTA123ES/-3Screws Nuts and Washers Door PartsMiscellaneous Model Number HOW to Order Replacement PartsPacking and Accessories DescriptionOven Control Panel Parts Door Parts Miscellaneous 930AK 930AW
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R-930AW specifications

The Sharp R-930 series of microwave ovens, including the R-930AK, R-930AW, and R-930CS models, represent a blend of advanced technology and user-centric design. These units are well-suited for modern kitchens, offering convenience, versatility, and efficiency that meet the needs of busy households.

One of the standout features of the R-930 series is the powerful Inverter Technology. Unlike traditional microwaves that rely on pulsing power to cook food at lower settings, Inverter Technology delivers a steady stream of cooking power. This results in more even heating, improved texture, and better overall cooking results for delicate dishes like custards and sauces.

The spacious interior of these models provides ample room for cooking a variety of dishes simultaneously. The R-930 series is designed with a turntable that ensures uniform cooking by rotating food as it heats. Additionally, these microwaves often come with a variety of pre-programmed settings for popular dishes, making it easier for users to prepare meals with minimal effort. These presets take the guesswork out of cooking and help ensure consistent results every time.

The R-930AK and R-930AW models are particularly noted for their sleek and modern aesthetic, available in stylish black and white exteriors, respectively. Both models also feature user-friendly controls, which include a digital display and intuitive buttons, ensuring that even those new to microwave cooking can navigate settings with ease.

Another characteristic that distinguishes the R-930CS is its advanced sensor cooking technology. This feature monitors the cooking process and automatically adjusts power levels and cooking times to achieve optimal results. This takes the hassle out of determining how long to cook various foods, especially those that require specific attention to avoid overcooking or undercooking.

The Sharp R-930 series also emphasizes safety and convenience. Child safety locks are integrated into the design to prevent unauthorized use, making it a practical choice for families with young children. Moreover, the easy-clean interior ensures that spills and splatters can be quickly wiped away, maintaining hygiene and preserving the appliance's appearance.

In summary, the Sharp R-930AK, R-930AW, and R-930CS models are proficient microwave ovens equipped with innovative technologies and thoughtful features that cater to a variety of cooking needs. With their combination of inverter cooking technology, spacious interiors, sleek designs, and user-friendly controls, these models are ideal choices for anyone looking to enhance their culinary capabilities in a fast-paced world.
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