R-22AT

R-24AT

 

TEST PROCEDURES

PROCEDURE

 

LETTER

COMPONENT TEST

 

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) Cooking is not possible.

NKEY UNIT TEST

CARRY OUT 3D CHECKS.

If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable is making good contact, verify that the stop switch operates properly; that is the contacts are closed when the door is closed and open when the door is open. If the stop switch is good, disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the stop switch is closed (either close the door or short the stop switch connector ). Use the key unit matrix indicated on the control panel schematic and place a jumper wire between the pins that correspond to the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a beep, the key unit is faulty and must be replaced. If the control unit does not respond, it is faulty and must be replaced. If a specific pad does not respond, the above method may be used (after clearing the control unit ) to determine if the control unit or key pad is at fault.

CARRY OUT 4R CHECKS.

G1

G9

G10

G11

G12

G2

G3

G4

177

18

8

199

200

G5

155

166

G6

133

144

G7

111

122

G8

ORELAY TEST

CARRY OUT 3D CHECKS.

Remove the outer case and check voltage between Pin Nos. 3 and 5 of the connector (A) on the control unit with an A.C. voltmeter. The meter should indicate 230 - 240 volts, if not check control unit circuity.

RY1, RY3 and RY4 Relay Test

These relays are operated by D.C. voltage.

Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.

DC. voltage indicated

Defective relay.

DC. voltage not indicated

Check diode which is connected to the relay coil. If

 

 

diode is good, control unit is defective.

 

 

 

RELAY SYMBOL

OPERATIONAL VOLTAGE

CONNECTED COMPONENTS

RY1

APPROX. 25.9V D.C.

Oven lamp, Blower motor and Antenna motors

RY3

APPROX. 25.0V D.C.

High voltage transformer (MG1)

RY4

APPROX. 25.0V D.C.

High voltage transformer (MG2)

CARRY OUT 4R CHECKS.

PPROCEDURES TO BE TAKEN WHEN THE FUSE ON THE PRINTED WIRING BOARD(PWB) IS OPEN

To protect the electronic circuits, this model is provided with a fine fuse added to the primary on the PWB. If the fuse is open, follow the troubleshooting guide given below for repair.

Problem: POWER ON, indicator does not light up.

CARRY OUT 3D CHECKS.

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Sharp R-24AT, R-22AT service manual KEY Unit Test, Relay Test, RY1, RY3, RY4

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.