Sharp R-24AT, R-22AT service manual Operation Sequence, Idle Condition, Microwave Cooking Condition

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R-22AT

R-24AT

OPERATION SEQUENCE

Closing the door activates all door interlock switches (interlock switches and stop switch).

IMPORTANT

When the oven door is closed, the monitor switch contacts COM-NC must be open. When the microwave oven is plugged in a wall outlet (230 - 240 volts, 50Hz), the line voltage is supplied to the control unit through the noise filter.

Figure O-1 on page 32

1. The digital display shows .

IDLE CONDITION

When the door is opened, the contacts of the interlock switches SW1+SW2 and stop switch SW5 open, initiating the following:

Figure O-2 on page 32

1.A signal is input to the control unit energizing the coil of shut-off relay RY-1.

2.The shut-off relay RY-1 contacts close completing circuits to turn on the oven lamp, blower motor and antenna motors.

3.If the door remains open, 60 seconds later the control unit de-energizes shut-off relay RY-1 turning off the oven lamp, blower motor and antenna motors.

When the door is closed, the contacts of the interlock switches SW1+SW2 and stop switch SW5 close. With the closing of the stop switch SW5 contacts, an additional circuit is provided which will permit the operation of the oven when one of the touch pads is depressed. Since the control is enabled through the stop switch SW5, the door must be closed before the touch pads will be effective. When the door is closed, a full 60 second IDLE condition is always provided for selecting and pressing the desired touch pads. A 60 second IDLE condition will also follow the end of each cook cycle.

MICROWAVE COOKING CONDITION

Touch MANUAL/REPEAT key and enter a desired cooking time with the touching NUMBER key. And then touch START key.

NOTE: The programme and the check are canceled when any keys are not touched for more than 3 minutes during programming.

Function sequence Figure O-3 on page 33

CONNECTED COMPONENTS

RELAY

Oven lamp/ Blower motor/ Antenna motors

RY1

 

 

High voltage transformer T1

RY3

to negative voltage of approximately 4000 volts D.C..

3.The 2450 MHz microwave energy produced in the magnetron generates a wave length of 12.24 cm. This energy is channelled through the waveguide (transport channel) into the oven cavity, where the food is placed to be cooked.

4.When the cooking time is up, a signal tone is heard and the relays RY3+RY4 go back to their home position. The circuits to the high voltage transformers T1+T2. The relay RY1 remains and oven lamp, blower motor and antenna motors work for 1 minute.

5.When the door is opened during a cook cycle, the switches come to the following condition.

 

 

CONDITION

 

 

DURING

DOOR OPEN

SWITCH

CONTACT

COOKING

(NO COOKING)

 

 

 

 

Interlock switches

COM-NO

Closed

Open

 

 

 

 

Monitor switches

COM-NC

Open

Closed

 

 

 

 

Stop switch

COM-NO

Closed

Open

 

 

 

 

The circuits to the high voltage transformers T1+T2 are cut off when the interlock and stop switches SW1+SW2+SW5 are made open. The blower motor BM, antenna motors and oven lamp remains on even if the oven door is opened after the cooking cycle has been interrupted, because the relay RY1 stays closed. Shown in the display is the remaining time, but the program is cancelled if the oven is not started within 1 minute.

6. MONITOR SWITCH CIRCUIT

The monitor switches SW3+SW4 are mechanically controlled by oven door, and monitors the operation of the interlock switches SW1+SW2.

6-1. When the oven door is opened during or after the cycle of a cooking program, the interlock switches SW1+SW2 and stop switches SW5 must open their contacts first. After that the contacts (COM-NC) of the monitor switches SW3+SW4 can be closed.

6-2. When the oven door is closed, the contacts (COM- NC) of the monitor switches SW3+SW4 must be opened first. After that the contacts (COM-NO) of the interlock switches SW1+SW2 and stop switch SW5 must be closed.

6-3. When the oven door is opened and the contacts of the interlock switch SW1 (or SW2) remain closed, re- mains closed, the fuse F1 F10A (or F2 F10A) will blow, because the monitor switch SW3 (or SW4) is closed and a short circuit is caused.

High voltage transformer T2

RY4

MICROWAVE VARIABLE COOKING

1.The line voltage is supplied to the primary winding of the two high voltage transformers. The voltage is converted to about 3.3 volts A.C. output on the filament winding and high voltage of approximately 2000 volts A.C. on the secondary winding.

2.The filament winding voltage (3.3 volts) heats the magnetron filament and the high voltage (2000 volts) is sent to the voltage doubling circuit, where it is doubled

When the microwave oven is preset for variable cooking power, the line voltage is supplied to the high voltage transformers T1+T2 intermittently within a 48 second time base through the contacts of the relays RY3+RY4.

The following levels of microwaves power are given.

4

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Contents Table of Contents Commercial Microwave OvenRemember to Check 3D Remember to Check 4R22AT/ R-24AT Sharp Corporation OSAKA, JapanCommercial Microwave Oven General Important InformationThis Appliance Must be Earthed SpecificationDescription Brown LiveAppearance View Installation InformationDisplay and Indicators Auto Touch Control PanelMicrowave Cooking Condition Operation SequenceIdle Condition Microwave Variable CookingTWO Magnetron Operation System Figure B-1. High Voltage CircuitFunction of Important Components Troubleshooting Guide Possible Cause and Defective Parts EEP ROM KEY Unit Touch Control Transformer T3Test Procedures Procedure Letter Component Test Magnetron TestMicrowave Output Power 1 litre water load Test Procedures Letter Component Test PowerMicrowave Output Power 2000 cc alternative method Carry OUT 4R Checks High Voltage Rectifier Assembly Test Carry OUT 3D ChecksSwitch Test Carry OUT 4R ChecksWeak Point F3 Test Carry OUT 3D Checks Procedure Letter Component TestTemperature Fuse TF1, TF2, TF3 Test Fuse F1, F2 F10A Test Carry OUT 3D ChecksNoise Filter Test Touch Control Panel Assembly TestMotor Winding Test High Voltage Fuse F4, F5 Test Carry OUT 3D ChecksRY1 KEY Unit TestRelay Test RY3Occurrence Cause or Correction Touch Control Panel Assembly Description of LSI LSIIXA222DRInternal clock oscillation frequency setting input Signal to sound buzzerSignal synchronized with commercial power source frequency Power source voltageDigit selection signal Key strobe signalSound Voltage level control terminal Servicing Shapes of Electronic ComponentsServicing of Touch Control Panel Other Precautions Servicing ToolsPAD Order Display Phone Procedure for Entering to Other Checking and Clearing PROCE- Dure forDefrost Using lead-free wire solder Precautions for Using LEAD-FREE SolderSET Number Double Quantity Check Signal Employing lead-free solderComponent Replacement and Adjustment Procedure Outer CASE, Rear Cabinet and Power Supply Cord RemovalHigh Voltage Transformers Removal Magnetrons Removal Magnetron Thermistor ReplacementRe-install RemovalBlower Motor Removal HOW to Release the Positive Lock ConnectorTerminal Insulator Replacement Stirrer Motors Upper and Lower RemovalControl Panel Assembly Removal Control Panel Assembly and Control Unit RemovalPower Supply Cord Replacement HOW to Attach Membrane Switch and Graphic SheetDoor Replacement and Adjustment After adjustment, make sure of the followingRemoval Door Disassembly Choke Cover RemovalDoor Components Removal Door Case Removal Service InformationUpper and Lower Latch Heads Removal Door Glass RemovalProcedure Microwave MeasurementPreparation Figure O-1 Oven Schematic-OFF Condition Figure O-3 Oven Schematic-Cooking Condition Figure S-1. Pictrorial Diagram PanelCircuit DG1Figure S-3. Printed Wiring Board Electoric Parts Parts ListParts marked * are used in voltage more than Cabinet PartsOven Parts RH-IXA222DRZZ LSI RH-IXA298DRZZ EepromDoor Parts MiscellaneousSCRE,NUTS and Washers HOW to Order Replacement Parts Packing and AccessoriesModel Number 2. REF. no Description Oven and Cabinet Parts Control Panel Parts Door Parts Miscellaneous
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R-22AT, R-24AT specifications

The Sharp R-24AT and R-22AT microwave ovens are advanced kitchen appliances designed to enhance cooking convenience, efficiency, and versatility. Both models incorporate innovative technologies and features that cater to modern cooking needs.

The Sharp R-24AT boasts a robust 900 watts of cooking power, enabling users to prepare a wide variety of meals quickly and effectively. Its spacious 24-liter capacity is suitable for families and those who enjoy entertaining. One of the standout features of the R-24AT is its intelligent sensor technology, which automatically detects humidity levels in the cooking food. This innovative feature ensures optimal cooking times and temperatures, resulting in perfectly cooked dishes without the guesswork.

Another key technology in the R-24AT is the inverter cooking system. This system provides a seamless flow of power throughout the cooking process, allowing for more precise temperature control. Unlike traditional microwaves that operate in full power or off, inverter technology ensures consistent heat, which is particularly beneficial for tasks such as defrosting, reheating, and simmering.

The Sharp R-22AT, while slightly more compact with a 22-liter capacity, also delivers impressive performance with 800 watts of power. It features a similar inverter cooking system that guarantees even cooking results. Both models come with multiple auto-cook presets, providing users with a selection of quick options for common dishes such as popcorn, pizza, and oatmeal. This feature streamlines meal preparation and reduces the time spent on planning meals.

In addition, the user-friendly control panel on both models includes a combination of push-button and rotary dial controls for easy navigation. The inclusion of a bright LED display further enhances usability, allowing cooks to monitor cooking times and settings easily.

Safety is another critical aspect of the Sharp R-24AT and R-22AT. Both models come equipped with a child lock feature, ensuring peace of mind in homes with young children. The stainless steel interiors of these microwaves facilitate easy cleaning, while their sleek design adds a modern touch to any kitchen.

In summary, the Sharp R-24AT and R-22AT microwave ovens stand out for their advanced cooking technologies, user-friendly features, and thoughtful design. They empower home cooks to prepare meals with precision and ease, making them a valuable addition to any kitchen.
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