Function Of Important Components - Sharp R-3S56 Service Manual

DOOR OPEN MECHANISM
The door is 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
latch hook. Now, the door can be opened.
LATCH HOOK
DOOR
LATCH
HEADS
DOOR OPEN BUTTON
Figure D-1. Door Open Mechanism
1ST. LATCH SWITCH, 2ND. LATCH SWITCH AND
STOP 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 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,
MONITOR SWITCH AND MONITOR RESIS-
TOR FOR PROPER OPERATION. (REFER
TO CHAPTER "TEST PROCEDURE")
MONITOR RESISTOR R 0.8
The monitor resistor prevents the fuse bursting when the
fuse blows due to the operation of the monitor switch.
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.

FUNCTION OF IMPORTANT COMPONENTS

MONITOR SWITCH
1ST. LATCH SWITCH
STOP SWITCH
2ND. LATCH SWITCH
SWITCH LEVER
Ω
20W
2. If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
TEMPERATURE FUSE 150˚C (MG)
This fuse protects the magnetron against overheating. If the
temperature goes up higher than 150˚C because the fan
motor is interrupted, the air inlet duct is blocked or the
ventilation openings are obstructed, the fuse blows and cuts
off the power supplying to the power transformer.
The defective fuse must be replaced with new rated one.
TEMP. FUSE 150˚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
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 150˚C,
causing the oven to shut down. The defective fuse must be
replace with a new one.
THERMAL CUT-OUT 95˚C
The thermal cut-out protect the fan motor against overheat.
If its temperature goes up higher than 95˚C because the fan
motor is locked or the ventilation openings are blocked, the
contacts of the thermal cut-out will open and switches off the
oven. When the oven cools itself down to 75˚C, the contacts
of the thermal cut-out will close again.
TURNTABLE MOTOR
The turntable motor drives the roller stay to rotate the
turntable.
FAN MOTOR FM
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 chan-
nelled through the oven cavity to remove steam and va-
pours given off from the heating foods. It is then exhausted
through the exhausting air vents at the oven cavity
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R-3S56