SHARP R-210A
Service Manual

R-210A

FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
The door can be opened by pushing the open button on the control panel. When the open button is pushed, the switch lever on the latch hook is moved upward, operating the latch head. The latch head is moved upward, and released from the latch hook. Now, the door can be opened.
LATCH HOOK

setting of cook time or failure of control unit. Under normal operation, the temp. fuse remains closed. However, when abnormally high temperatures are reached within the oven cavity, the temp. fuse will open at 120�C, causing the oven to shut down. The defective fuse must be replaced with a new one.

THERMAL CUT-OUT 95�C (MAGNETRON )
The thermal cut-out located on the top of the oven cavity is designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the thermal cut-out remains closed. However, when abnormally high temperatures are reached within the magnetron, the thermal cut-out will open at 95�C, causing the oven to shut down. When the magnetron has cooled to 75�, the thermal cut-out closes and cook cycle will resume.

LATCH HEADS

1ST. LATCH SWITCH

MONITOR SWITCH DOOR 2ND. LATCH SWITCH SWITCH LEVER

Figure D-1. Door Open Mechanism 1ST. LATCH SWITCH AND 2ND. LATCH SWITCH
1. When the oven door is closed, the contacts (COM-NO) must be closed. 2. When the oven door is opened, the contacts (COMNO) must be opened.

NOISE FILTER
The noise filter prevents the radio frequency interference that might flow back in the power circuit.

TURNTABLE MOTOR
The turntable motor drives the roller stay to rotate the turntable.

MONITOR SWITCH
1. When the oven door is closed, the contacts (COM-NC) must be opened. 2. When the oven door is opened, the contacts (COMNC) must be closed. 3. If the oven door is opened and the contacts (COM-NO) of the 1st latch switch and 2nd latch switch fail to open, the fuse blows simultaneously with closing the contacts (COM-NC) of the monitor switch. CAUTION: BEFORE REPLACING A FUSE TEST THE 1ST LATCH SWITCH, 2ND LATCH SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE".)

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.

TIMER MOTOR (WITH VARI-SWITCH)
Timer switch 1. When the timer is at "0" position, the switch of the timer are opened. 2. When the timer is turned clockwise from "0" position, the switch of the timer are closed. Vari-switch If the variable cooking control is set at HIGH, MEDIUM HIGH, MEDIUM, MEDIUM LOW or LOW cooking position, Rated voltage is supplied to the power transformer intermittently within a 30 seconds time base. The following chart shows the vari-switch operation in the various modes. SETTING
HIGH 30 sec. ON Approx. 100% 23.2 sec. ON MEDIUM HIGH 16.5 sec. ON MEDIUM 13.5 sec. OFF Approx. 50% 9.8 sec. ON 20.2 sec. OFF MEDIUM LOW 5.0 sec. ON LOW 25 sec. OFF Approx. 10% Approx. 30% 6.8 sec. OFF Approx. 70%

FUSE
1. The fuse blows when the contacts (COM-NO) of the 1st latch switch and 2nd latch switch remain closed with the oven door open and when the monitor switch closes. 2. If the wire harness or electrical components are shortcircuited, the fuse blows to prevent an electric shock of fire hazard.

HIGH VOLTAGE FUSE
The high voltage fuse blows when the high voltage rectifier or the magnetron is shorted.

TEMPERATURE FUSE 120�C (OVEN)
The temp. fuse 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
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