R420LW
6 – 2
3. Sensor detects moisture and humidity and calculates cooking time
and variable power.
5.1. Cooking Sequence.
1. Operate the oven in sensor cooking mode by referring to the opera-
tion manual.
NOTE: The oven should not be operated on SENSOR immediately
after plugging in the unit. Wait two minutes before cooking on
SENSOR.
2. The coil of shut-off relay (RY-1) is energized, the turntable motor,
oven lamp and cooling fan motor are turned on, but the power
transformer is not turned on.
3. After about 16 seconds, the cook relay (RY-2) is energized. The
power transformer is turned on, microwave energy is produced and
first stage is started. The 16 seconds is the cooling time required to
remove any vapor from the oven cavity and sensor.
NOTE: During this first stage, do not open the door or touch STOP/
CLEAR pad.
4. When the sensor detects the vapor emitted from the food, the dis-
play switches over to the remaining cooking time and the timer
counts down to zero. At this time, the door may be opened to stir,
turn, or season food.
5. When the timer reaches zero, an audible signal sounds. The shut-
off relay and cook relay are de-energized and the power trans-
former, oven lamp, etc. are turned off.
6. Opening the door or touching the STOP/CLEAR pad, the time of
day will reappear on the display and the oven will revert to an OFF
condition.
[2] OVEN SCHEMATIC
1. Off Condition
Figure O-1. Oven Schematic-Off Condition
MICROWAVE
AH SENSOR
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
NOTE: " " indicates components with potentials above 250V
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
C1:
LINE CROSS CAPACITOR ------- 0.22uF/ AC250V
C2, C3: LINE BYPASS CAPACITOR ------ 0.033uF/ AC250V
BLK
NOISE
FILTER
MONIT
OR
FUSE
(20A)
"T
O
LOAD"
"T
O
LOAD"
"T
O
S
OURCE"
"T
O
S
OURCE"
AH
SENSOR
F-3
F-2
F-1
