Sensor Cooking Condition - Sharp R-1880LS Service Manual

R-1880LS/LST
sends a signal to the LSI on the control unit de-energizing the
relay (RY6) and opening the circuit to the damper motor.
3. The coil of heater relay (RY3) is energized by the control
unit and the main supply voltage is applied to the heating
element.
4. When the oven temperature reaches the selected preheat
temperature, the following operations occur:
4-1 The heater relay is de-energized by the control unit
temperature circuit and thermistor, opening the circuit
to the heating element.
4-. The oven will continue to function for 30 minutes, turning
the heater on and off, as needed to maintain the selected
preheat temperature. The oven will shutdown completely
after 30 minutes
CONVECTION COOKING CONDITION
When the preheat temperature is reached, a beep signal will sound
indicating that the holding temperature has been reached in the
oven cavity. Open the door and place the food to be cooked in
the oven.
Program convection temperature and desired cooking time by
touching the CONVEC pad, Temperature pad and NUMBER
pad.
When the START pad is touched, the following operations oc-
cur:
1. The numbers on the digital read-out start to count down to
zero.
. The oven lamp, turntable motor, cooling fan motor and
convection motor are energized.
3. Heater relay (RY3) is energized (if the cavity temperature
is lower than the selected temperature) and the main supply
voltage is applied to the heating element to return to the selected
cooking temperature.
4. Upon completion of the cooking time, the audible signal
will sound, and oven lamp, turntable motor, cooling fan
motor and convection motor are de-energized. At the end of
the convection cycle, if the oven temperature is above 75
F, the circuit to RY5 will be maintained (by the thermistor
circuit) to continue operation of the cooling fan motor until
the temperature drops below 45
will be de-energized, turning off the fan motor. Relay RY7
will however, open as soon as the convection cycle has ended,
turning off the convection motor.
5. A t the end of the convection cook cycle, shut-off relay (RY6) is
energized turning on the damper motor. The damper is returned
to the open position, closing the damper switch contacts which
send a signal to the control unit, de-energizing shut-off relay
(RY6).
AUTOMATIC MIX COOKING CONDITION
Touch the Combination Bake or Combination Roast pad. The
LOW MIX/BAKE pad is preprogrammed for 35
microwave power, while the HIGH MIX/ROAST pad is pre-
ο
programmed for 35 F with 30% microwave power. Program
desired cooking time. When the START pad is touched, the fol-
lowing operations occur:
1. The numbers on the digital read-out start to count down to
zero.
. The shut-off relays (RY1, RY4, RY5 and RY7) are energized,
turning on the oven lamp, turntable motor, cooling fan motor
and convection motor.
3. The shut-off relay (RY6) is energized.
The damper plate is closed from the open position.
4. The heater relay (RY3) is energized, applying the main supply
voltage to the heating element.
ο
ο
F, at which time the relay
ο
F with 10%
1
5. Now, the oven is in the convection cooking condition.
6. When the oven temperature reaches the selected temperature,
the following operations occur:
6-1. The power supply voltage is alternated to the heating
element and power transformer.
6-. The heating element operates through the heater relay
(RY3) contacts and the power transformer operates
through the primary interlock relay (RY) contacts.
6-3. These are operated by the control unit to supply alternately
within a 3 second time base, convection heat and
microwave energy.
The relationship between the convection and microwave power
operations are as follows.
Note: The ON and OFF time ratio does not correspond with
the percentage of microwave power, because approx.
 seconds are needed for heating of the magnetron
filament.
Note: During alternate Microwave/Convection operation,
the convection heater is energized only if the cavity
temperature drops below the set temperature.
6 SEC. 26 SEC.
ON
(MICRO.)
OFF
(CONVEC.)
LOW MIX
BAKE
12 SEC. 20 SEC.
ON
(MICRO.)
OFF
ON
(CONVEC.)
OFF
32 SEC.
HIGH MIX
ROAST

SENSOR COOKING CONDITION

Using the SENSOR COOK, SENSOR REHEAT or POPCORN
function, the foods are cooked or defrosted without figuring time,
power level or quantity. When the oven senses enough steam from
the food, it relays the information to its microprocessor which
will calculate the remaining cooking time and power level needed
for 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 according to the menu, sup-
plementary cooking is started.
MICROWAVE POWER
= APPROX. 10%
CONVECTION
TEMPERATURE
= 325ûF (165ûC)
MICROWAVE POWER
= APPROX. 30%
CONVECTION
TEMPERATURE
325ûF (165ûC)