Chapter 6. Function Of Important Compo; Door Open Mechanism; Monitored Latch Switch And Latch Switch; Monitor Switch - Sharp R-20A1(S)VN Service Manual

R-20A1(S)VN
CHAPTER 6.
FUNCTION OF IMPORTANT COMPONENTS
R218L(W)

[1] DOOR OPEN MECHANISM

The 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.
Latch Heads
Door
Switch Lever
Figure D-1. Door Open Mechanism
[2] MONITORED LATCH SWITCH AND
LATCH SWITCH
1. When the oven door is closed, the contacts (COM-NO) must be
closed.

[3] 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 mon-
itored latch switch, the contacts of the relay RY1 and the timer
switch fail to open, the fuse T6.3A blows immediately after closing
the contacts (COM-NC) of the monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE TEST THE MON-
ITORED LATCH SWITCH, RELAY RY1, TIMER SWITCH
AND MONITOR SWITCH FOR PROPER OPERATION.
(REFER TO CHAPTER "TEST PROCEDURE".)

[4] FUSE T6.3A

1. The fuse T6.3A blows when the contacts (COM-NO) of the moni-
tored latch switch, the contacts of the relay RY1 and the timer
switch remain closed with the oven door open and when the con-
tacts (COM-NC) of the monitor switch are close.
2. If the wire harness or electrical components are short-circuited, the

[5] HIGH VOLTAGE FUSE

netron is shorted.
Latch Hook
Monitored
Latch Switch
Monitor Switch
Latch Switch
6 – 1

[6] TEMPERATURE FUSE 150C (OVEN)

The temperature fuse located on the top of the oven cavity is designed
by either error in cook time or defect in the control unit, the tempera-
ture 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. The defective temperature fuse
must be replaced with a new one.

[7] TURNTABLE MOTOR

The turntable motor drives the turntable roller assembly to rotate the
turntable.

[8] 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
exhausted through the exhausting air vents at the oven cavity.

[9] TIMER MOTOR

Timer switch
1. When the timer switch is at "0" position, the switch of the timer is
opened.
2. When the timer is turned clockwise from "0" position, the switch of
the timer is closed.