Sharp R-2397 - Manual (Page 7)

5
R-2397
FUNCTION OF IMPORTANT COMPONENTS
MONITOR SWITCH
The monitor switch is activated (the contacts opened) the
upper latch head and switch lever A while the door is
closed. The switch is intended to render the oven inopera-
tive by means of blowing the fuse F6.3A when the
contacts of the 1st latch switch fail to open when the door
is opened.
Function
1. When the door is opened, the monitor switch contacts
close (to the ON condition) due to their being normally
closed. At this time the 1st latch switch is in the OFF
condition (contacts open) due to their being normally
open contact switches.
2. As the door goes to a closed position, the monitor
switch contacts are opened and 1st latch switch con-
tacts are closed (On opening the door, each of these
switches operate inversely.)
3. If the door is opened and the 1st latch switch contacts
fail to open, the fuse F6.3A blows simultaneously with
closing of the monitor switch contacts.
CAUTION:BEFORE REPLACING A BLOWN FUSE
F6.3A TEST THE 1ST LATCH SWITCH,
MONITOR SWITCH AND MONITOR RESIS-
TOR FOR PROPER OPERATION. (REFER
TO CHAPTER “TEST PROCEDURE”).
MONITOR RESISTOR
The monitor resistor prevents the fuse F6.3A 250V burst-
ing when the fuse F6.3A 250V blows due to the operation
of the monitor switch.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
WEAK POINT
If the wire harness or electrical components make a short-
circuit, this weak point blows to prevent an electric shock
or fire hazard.
DOOR OPEN MECHANISM
1. The door release lever is pulled.
2. The upper latch head is lifted up by the linked door
release lever.
3. The latch lever is lifted up by the door release lever.
4. The joint lever is lifted up by the latch lever.
5. The lower latch head is lifted up by the joint lever.
6. Now both latch heads are lifted up, so they can be
released from the latch hook.
7. Now the door can be opened.
Latch head
Monitor switch
Latch hook
1st. latch switch
2nd. latch switch
Stop switch
3rd. latch switch
Latch head
Joint lever
Door release
lever
Figure D-1. Door Open Mechanism
1ST LATCH SWITCH, 2ND LATCH SWITCH, 3RD
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.
COMMERCIAL
FREQUENCY
(50HZ)
POWER OUTPUT
BY MAGNETRON 1
POWER OUTPUT
BY MAGNETRON 2
OPERATION OF
MAGNETRON
T1: HIGH VOLTAGE
TRANSFORMER
ASYMMETRIC RECTIFIER
H. V. RECTIFIER
C1: H.V. CAPACITOR
MG1: MAGNETRON (UPPER)
(REAR)
ASYMMETRIC RECTIFIER
H. V. RECTIFIER
C2: H.V. CAPACITOR
MG2: MAGNETRON (LOWER)
T2: HIGH VOLTAGE
TRANSFORMER
(FRONT)
Figure B-1. High Voltage Circuit Figure B-2. Operation of Magnetron