SHARP R-22AT
Service Manual

R-22AT R-23AM R-24AT

cavity, the oven temperature fuse will open at 120�C, causing the oven to shut down. The defective temperature fuse must be replaced with new rated one.

MAGNETRON THERMISTOR
The thermistor is a negative temperature coefficient type. The air temperature around the upper magnetron is detected through the resistance of the thermistor. If the temperature is high, the control panel will display "EE17" and the oven will stop to protect the lower magnetron against overheat. If the oven thermistor (2) and the magnetron thermistor are open at the same time, the control panel will display "EE16" and the oven will stop.

BLOWER MOTOR TEMPERATURE FUSE TF3
This temperature fuse TF3 protects the blower motor against overheating. If its temperature goes above 120�C because the blower motor is stalled or the ventilation openings are blocked, the contacts of the temperature fuse will open. The line voltage to the control unit will be cut off and the operation of the oven will be stopped. The defective temperature fuse must be replaced with a new one.

BLOWER MOTOR BM
The blower motor BM drives a blade which draws external cool air into the oven. This cool air is directed through the air vanes surrounding the magnetrons and cools the magnetrons. This air is channelled through the oven cavity to remove steam and vapours given off from the heating foods. It is then exhausted through the exhausting air vents at the oven cavity.

OVEN THERMISTOR (1)
The thermistor is a negative temperature coefficient type. The temperature in the exhaust duct is detected through the resistance of the thermistor. If the temperature is high, the control panel will display �EE7� and the oven will stop to avoid overheating and catching fire. If the thermistor is open, the control panel will display "EE6" and the oven will stop.

STIRRER MOTORS SM
The upper and lower stirrer motors SM drive stirrer antennas to stir the microwave radiation from the upper and lower waveguides.

OVEN THERMISTOR (2)
This thermistor detects temperature of the oven cavity bottom plate. The thermistor is a negative temperature coefficient type. The temperature is detected through the resistance of the thermistor. If the temperature is high, the control will display �EE17� and the oven will stop.

OVEN LAMP OL
The oven cavity light illuminates the interior of the oven so that food being cooked can be examined visually through the door window without having to open the door. The oven lamp is on during the cooking cycle and idle condition.

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 fuse F2 F6.3A in the 1st latch switch SW1 - monitor switch SW4 - monitor resisitor R1 circuit, check the 1st latch switch SW1, monitor switch SW4 and monitor resistor R1 before replacing the fuse F2 F6.3A

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