Function Of Important Components - Sharp R-90GCH Service Manual

R-90GCH
The LSI also stops counting down and closes the
damper door so that no fresh air will enter the oven
cavity.
4. Once the fire sensor feature has shut the unit down, the
programmed cooking cycle may be resumed by
pressing the "START" pad or the unit may be reset by
pressing the "CLEAR" pad.
DOOR OPEN MECHANISM
The door is opened by pulling the door handle down and
forward, referring to the figure D-1. When the door handle
is pulled down, the latch heads are moved upward. And
then when the door handle is pulled forward, the latch
heads are released from the latch hooks right and left.
Now, the door will open.
SW2:
Monitor switch
SW1:
Latch
Secondary
head
interlock switch
(Monitored latch switch)
Latch hook right
Door handle
Figure D-1. Door Open Mechanism
DOOR SENSING SWITCH SW4, SECONDARY
INTERLOCK SWITCH SW1 AND 3RD. LATCH
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.
2. When the oven door is opened, the contacts (COM-

FUNCTION OF IMPORTANT COMPONENTS

Latch hook left
SW3:
3rd. latch
switch
Latch
head
SW4:
Door
sensing switch
(Primary interlock
relay control switch)
0 2 3
CONVECTION
MOTOR ON
OFF
3 sec.
THERMISTOR
ON
OFF
ON
Sensing
Voltage
OFF
Sensing the voltage across temperature measurement circuit.
NC) must be closed.
3. If the oven door is opened and the contacts (COM-NO)
of the secondary interlock switch SW1 and the relay
RY2 fail to open, the fuse F10A blows simultaneously
with closing the contacts (COM-NC) of the monitor
switch SW2.
CAUTION: BEFORE REPLACING A FUSE TEST THE
SECONDARY INTERLOCK SWITCH SW1,
RELAY RY2 AND MONITOR SWITCH SW2
FOR PROPER OPERATION. (REFER TO
CHAPTER "TEST PROCEDURE".)
FUSE F2 (F10A)
1. The fuse F2 (F10A) blows when the contacts (COM-
NO) of the secondary interlock switch SW1 and relay
RY2 remain closed with the oven door open and when
the monitor switch closes.
2. If the wire harness or electrical components are short-
circuited, the fuse F2 (F10A) blows to prevent an
electric shock of fire hazard.
HIGH VOLTAGE FUSE F3
The high voltage fuse F3 blows when the high voltage
rectifier or the magnetron is shorted.
NOISE FILTER
The noise filter prevents the radio frequency interference
that might flow back in the power circuit.
THERMISTOR
The thermistor is a negative temperature coefficient type.
The temperature in the oven cavity is detected through the
resistance of the thermistor, and then the control unit causes
the heater relay to operate, thus the current to the heating
elements is turned ON/OFF. If the convection cooking or
some cooking modes which use the top / side heating
elements is started and the oven temperature does not rise
above 37.8˚C, the control unit will stop the oven after 10
minutes. In this case, the thermistor may be opened.
10
28 31 32 (sec.) 64 (sec.)
3 sec.