Sharp R-4H56, Service Manual

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R-4H56
5
best results.
When the food is cooked, water vapor is developed. The
sensor “senses” the vapor and its resistance increases
gradually. When the resistance reaches the value set ac-
cording to the menu, supplementary cooking is started.
The time of supplementary cooking is determined by experi-
ment with each food category and inputted into the LSI.
An example of how sensor works: ACTION immediately after plugging in the unit. Wait
five minutes before cooking on SENSOR COOK,
REHEAT SENSOR or SENSOR INSTANT ACTION.
2. Select desired Sensor setting.
3. Touch START pad (REHEAT SENSOR and SENSOR
INSTANT ACTION fuction are not neccessary to touch
START pad.) 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.
4. 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.
5. When the sensor detects the vapor emitted from the
food, the display switches over to the remaining cooking
time and the timer counts down to zero.
At this time, the door may be opened to stir food, turn it
or season, etc.
6. When the timer reaches zero, an audible signal sounds.
The shut-off relay and cook relay are de-energized and
the power transformer, oven lamp, etc. are turned off.
7. 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.
1. Potatoes at room temperature.
Vapor is emitted very slowly.
2. Heat potatoes. Moisture and
humidity is emitted rapidly. You
can smell the aroma as it
cooks.
3. Sensor detects moisture and
humidity and calculates
cooking time and variable
power.
Cooking Sequence.
1. Touch each SENSOR COOK function pad to operating
the sensor cooking.
NOTE: The oven should not be operated on SENSOR
COOK, REHEAT SENSOR or SENSOR INSTANT
MICROWAVE
MICROWAVE
AH SENSOR
FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
The door can be opened by pushing the door open button on
the control panel. When the door open button is pushed, the
latch lever is moved upward, operating the latch head. The
latch head is moved upward, and released from the latch
hook. Now, the door can be opened.
MONITOR
SWITCH
UPPER
LATCH
SWITCH
STOP
SWITCH
LOWER
LATCH
SWITCH
LATCH
LEVER
PLUNGER
SWICTH
LATCH
HEAD
DOOR
OPEN
BUTTON
LATCH
HEAD
LATCH
HOOK
DOOR
Figure D-1. Door Open Mechanism
UPPER LATCH SWITCH, LOWER 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.
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 upper and lower latch switches fail to open, the
fuse (M8A) blows simultaneously with closing the contacts
(COM-NC) of the monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE (M8A)
TEST THE UPPER AND LOWER LATCH
SWITCHES, MONITOR SWITCH AND MONI-
TOR RESISTOR FOR PROPER OPERATION.
(REFER TO CHAPTER “TEST PROCEDURE”.)
MONITOR RESISTOR (0.8
Ω
20W)
The monitor resistor prevents the fuse (M8A) bursting when
the fuse blows due to the operation of the monitor switch.