Read Sharp R-741M (serv.man2) Service Manual online
3
741M -
IMPORTANT
When the oven door is closed, the monitor switch contacts
COM - NC must be open.
When the oven door is closed, the monitor switch contacts
COM - NC must be open.
MICROWAVE COOKING CONDITION
HIGH COOKING
When the door is opened during a cook cycle, the switches
come to the following condition.
come to the following condition.
CONDITION
DURING
DOOR OPEN
SWITCH
CONTACT
COOKING
(NO COOKING)
Monitored latch switch
COM-NO
Closed
Open
Monitor switch
COM-NC
Open
Closed
COM-NO
Closed
Open
Stop switch
COM-NO
Closed
Open
When the oven door is opened and the contacts of the
monitored latch switch SW1 remain closed, the fuse F8A
will blow.
monitored latch switch SW1 remain closed, the fuse F8A
will blow.
MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
COOKING
The following levels of microwave power are given.
SETTING
DUAL COOKING CONDITION
1. The contact of primary latch switch SW1 are closed.
2. The relay RY1, RY2 and RY3 are energised.
3. When cooking in dual mode the microwave power is
2. The relay RY1, RY2 and RY3 are energised.
3. When cooking in dual mode the microwave power is
limited to 70% (via the I.C.).
Approx. 100%
Approx. 50%
Approx. 30%
30 sec. ON
HIGH
LOW
24 sec. ON
6 sec. OFF
18 sec. ON
10 sec. ON
5 sec. ON
12 sec. OFF
20 sec. OFF
25 sec. OFF
MEDIUM
MEDIUM HIGH
MEDIUM LOW
Approx. 70%
Approx. 10%
FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
Figure D-1. Door Open Mechanism
MONITOR
SWITCH
SWITCH
MONITORED
LATCH SW
LATCH SW
OPEN LEVER
DOOR
STOP SWITCH
DOOR OPEN BUTTON
LATCH HOOK
LATCH
HEAD
HEAD
MONITORED LATCH SWITCH SW1
STOP SWITCH SW3
STOP 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
I
I
f the oven door is opened and the contacts
(COM-NO) of the monitored latch switch SW1 fail
to open, the fuse F8A blows simultaneously with
closing the contacts (COM-NC) of the monitor
switch SW2.
to open, the fuse F8A blows simultaneously with
closing the contacts (COM-NC) of the monitor
switch SW2.
CAUTION: BEFORE REPLACING A BLOWN
FUSE F8A TEST THE MONITORED
LATCH SWITCH SW1, MONITOR
SWITCH SW2.
LATCH SWITCH SW1, MONITOR
SWITCH SW2.
OPERATING SEQUENCE
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