SHARP R-334 (W)
Manual de Servicio

FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM The door can be opened by pulling the door open. FUSE F1 F8A 250V 1. If the wire harness or electrical components are shortcircuited, this fuse blows to prevent an electric shock or fire hazard. 2. The fuse also blows when monitored latch switch SW1 remains closed with the oven door open and when the monitor switch SW2 closes. 3. The fuse blows when the asymmetric rectifier, H.V. rectifier, H.V. wire harness, H.V. capacitor, magnetron or secondary winding of power transformer is shorted. THERMAL CUT-OUT 125°C TC1 (MG) The thermal cut-out protects the magnetron against overheat. If this temperature goes up higher than 125°C because the fan motor is interrupted, the ventilation openings are blocked, the thermal cut-out TC1 will open and line voltages to the power transformer T will be cut off and the operation of the magnetron MG will be stopped. The defective thermal cut-out TC1 must be replaced with new one. THERMAL CUT-OUT 125°C TC2 (OVEN) The thermal cut-out located on the top of the oven cavity is designed to prevent damage to the oven if the foods in the oven catch fire due to over heating produced by improper setting of cook time or failure of control unit. Under normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at 125°C, causing the oven to shut down. The defective thermal cut-out TC2 must be replaced with new one. TURNTABLE MOTOR The turntable motor drives the turntable roller assembly to rotate the turntable. FAN MOTOR The fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetron and cools the magnetron. 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. NOISE FILTER The noise filter prevents the radio frequency interference that might flow back in the power circuit.

Latch Hooks

Stop Switch SW3

Monitor Switch SW2

Monitored Latch Switch SW1

Figure D-1. Door Open Mechanism MONITORED LATCH SWITCH SW1 STOP SWITCH SW3 1. When the oven door is closed, the contacts (COM - NO) must be closed. 2. When the oven door is opened, the contacts (COM - NO) must be opened. MONITOR SWITCH SW2 1. When the oven door is closed, the contacts (COM - NC) must be opened and the contacts (COM - NO) must be closed. 2. When the oven door is opened, the contacts (COM NC) must be closed and the contacts (COM - NO) must be open. 3. If the oven door is opened and the contacts (COM - NO) of the monitored latch switch SW1 fail to open, the fuse F1 F8A blows simultaneously with closing the contacts (COM - NC) of the monitor switch SW2. CAUTION: BEFORE REPLACING A BLOWN FUSE F1 F8A TEST THE MONITORED LATCH SWITCH SW1, MONITOR SWITCH SW2 FOR PROPER OPERATION. (REFER TO CHAPTER �TEST PROCEDURE�.)

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