R426LS
6 – 3
2. Cooking Condition
Figure O-2. Oven Schematic-Cooking Condition
[3] DESCRIPTION AND FUNCTION OF COMPONENTS
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 but-
ton 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.
Figure D-1. Door Open Mechanism.
2. DOOR SENSING AND PRIMARY INTERLOCK
SWITCHES
The primary interlock switch is mounted in the lower position of the
latch hook and the door sensing switch in the secondary interlock sys-
tem is mounted in the upper position of the latch hook. They are acti-
vated by the latch heads on the door. When the door is opened, the
switches interrupt the power to all high voltage components.
A cook cycle cannot take place until the door is firmly closed there by
activating both interlock switches. The secondary interlock system
consists of the door sensing switch and secondary interlock relay
located on the control circuit board.
3. MONITOR SWITCH
The monitor switch is activated (the contacts opened) by the latch
head on the door while the door is closed. The switch is intended to
render the oven inoperative, by means of blowing the monitor fuse,
when the contacts of the secondary interlock relay (RY2) and primary
interlock switch fail to open when the door is opened.
Functions:
1) When the door is opened, the monitor switch contact close (to the
ON condition) due to their being normally closed. At this time the
secondary interlock relay (RY2) and primary interlock switch are 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 first opened and then the door sensing switch and the primary
interlock switch contacts close. (On opening the door, each of these
switches operate inversely.)
3) If the door is opened, and the secondary interlock relay (RY2) and
primary interlock switch contacts fail to open, the monitor fuse
blows simultaneously with closing of the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITORFUSE TEST
THE DOOR SENSING SWITCH, SECONDARY INTER-
LOCK RELAY (RY2), RE-LAY (RY1), PRIMARY INTER-
LOCK SWITCH AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST PROCE-
DURE”).
NOTE:
MONITOR FUSE AND MONITOR SWITCH ARE REPLACED
AS AN ASSEMBLY.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME PROGRAMMED.
3. VARIABLE COOKING CONTROL "P-HI".
4. START PAD TOUCHED.
OVEN
THERMAL CUT-OUT
120VAC
60Hz
WHT
GRN
B2
B1
CONTROL UNIT
MAGNETRON
TEMPERATURE
FUSE
(RY2)
DOOR
SENSING
SWITCH
TTM
FM
OL
TURN
TABLE
MOTOR
FAN
MOTOR
OVEN
LAMP
MONITOR
SWITCH
PRIMARY INTERLOCK
SWITCH
POWER TRANSFORMER
MAGNETRON
HIGH
VOLTAGE
CAPACITOR
0.94uF/ AC2200V
SECONDARY
INTERLOCK
RELAY
GND
(RY1)
OVEN LAMP
RELAY
COM.
N.O.
COM.
N.C.
HIGH
VOLTAGE
RECTIFIER
H
N
C3
C2
C1
BLK
NOISE
FILTER
MONIT
OR
FUSE
(20A)
"T
O
LOAD"
"T
O
LOAD"
"T
O
S
OURCE"
"T
O
S
OURCE"
C1:
LINE CROSS CAPACITOR ------- 0.22uF/ AC250V
C2, C3: LINE BYPASS CAPACITOR ------ 0.033uF/ AC250V
AH
SENSOR
F-3
F-2
F-1
Door Sensing
Switch
Monitor Switch
Switch Lever
Primary Interlock
Switch
Latch Heads
Door
