Sharp R-330H Service Manual Download Page 7

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R-330H

FUNCTION OF IMPORTANT COMPONENTS

OVEN TEMPERATURE FUSE

The temperature fuse, located on the top of the oven
cavity, is designed to prevent damage to the oven by fire.
If the food load is overcooked, by either error in cook time
or defect in the control unit, the temperature fuse will open.
Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the temperature fuse will
open at 150˚C, causing the oven to shut down.

MAGNETRON TEMPERATURE FUSE

The temperature fuse located near the magnetron 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 temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the magnetron, the temperature fuse will
open at 150˚C causing the oven to shut down.

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 vents surrounding
the magnetron and cools the magnetron. This air is chan-
nelled through the oven cavity to remove steam and
vapours given off from the heating foods. It is then ex-
hausted 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.

DOOR OPEN MECHANISM

he door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
When the open button is pushed, the open button pushes
up the switch lever, and then the switch lever pushes up
the latch head. The latch heads are moved upward and
released from latch hook. Now the door will open.

Figure D-1. Door Open Mechanism

1ST. LATCH SWITCH AND 2ND. INTERLOCK
RELAY CONTROL SWITCH

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

1. When the oven door is closed, the contacts (COM-NC)

must be opened.

2. When the oven door is opened, the contacts (COM-

NC) must be closed.

3. If the oven door is opened and the contacts (COM-NO)

of the 1st. latch switch and 2nd. interlock relay fail to
open, the fuse F10A blows simultaneously with closing
the contacts (COM-NC) of the monitor switch.

CAUTION: BEFORE REPLACING A BLOWN FUSE F10A

TEST THE 1ST. LATCH SWITCH, 2ND.
INTERLOCK RELAY, MONITOR SWITCH
AND MONITOR RESISTOR FOR PROPER
OPERATION.

HIGH VOLTAGE FUSE

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

FUSE F10A

1. The fuse F10A blows when the contacts (COM-NO) of

the 1st. latch switch and 2nd. interlock relay remain
closed with the oven door open and when the monitor
switch closes.

2. If the wire harness or electrical components are short-

circuited, this fuse F10A blows to prevent an electric
shock or fire hazard.

Latch
Heads

Door

Switch Lever