Sharp Carousel R-880F Service Manual - Page 7

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1. The relay RY3 + RY5 + RY6 are energized.

2. The numbers of the digital read-out start the count

down to zero.

3. Then the top heaters, turntable motor, oven lamp and

fan motor are energized.

4. Now, the food is grilled by the top heaters.

5. Upon completion of the selected cooking time, audible

signal sounds and the contacts of relays RY3 + RY6

are opened, then the top heaters, turntable motor and

oven lamp are de-energized. But the relay RY5 stays

closed and the fan motor operates for 5 minutes. But if

the cooking time is less than 2 minutes the relay RY5

will not stay close.

HEATER

BOTTOM

MODE

In this mode, the food is cooked by the bottom heater.

Press the GRILL pad twice and then enter the cooking time

by pressing the number pads. When the START pad is

pressed, the following operations occur:

Figure O-3(b) on page 34

1. The relay RY4 + RY5 + RY6 are energized.

2. The numbers of the digital read-out start the count

down to zero.

3. Then the bottom heater, turntable motor, oven lamp

and fan motor are energized.

4. Now, the food is grilled by the bottom heater.

5. Upon completion of the selected cooking time, audible

signal sounds and the contacts of relays RY4 + RY6

are opened, then the bottom heating elements, turnta-

ble motor and oven lamp are de-energized. But the

relay RY5 stays closed and the fan motor operates for

5 minutes. But if the cooking time is less than 2 minutes

the relay RY5 will not stay close.

TOP AND BOTTOM HEATER MODE

In this mode, the food is cooked by both the top heaters

and bottom heater. Press the GRILL pad three times and

then enter the cooking time by pressing the number pads.

When the START pad is pressed, the following operations

occur:

Figure O-3(c) on page 35

1. The relay RY3 + RY4 + RY5 + RY6 are energized.

2. The numbers of the digital read-out start the count

down to zero.

3. Then the top heaters, bottom heater, turntable motor,

oven lamp and fan motor are energized.

4. Now, the food is grilled by the top heaters and the

bottom heater.

5. Upon completion of the selected cooking time, audible

signal sounds and the contacts of relays RY3 + RY4 +

RY6 are opened, then the top heating elements, bot-

tom heating element, turntable motor and oven lamp

are de-energized. But the relay RY5 stays closed and

the fan motor operates for 5 minutes. But if the cooking

time is less than 2 minutes the relay RY5 will not stay

closed.

MIX COOKING CONDITION

GRILL

The oven will cook food by supplying grill heaters (top

heaters or Bottom heater) and microwave energy alter-

nately within a 48 seconds time base. And the oven has

four programmed cooking mode.

HIGH MIX TOP GRILL MODE AND LOW MIX TOP

GRILL MODE

In these modes, the food is cooked by the top heaters and

the microwave energy. Press the MIX pad once for HIGH

MIX TOP GRILL mode. Press the MIX pad twice for LOW

MIX TOP GRILL mode. And then enter the cooking time

by pressing the number pads. When the START pad is

pressed, the following operations occur:

Figure O-5(a) on page 36

1. The relay RY5 + RY6 are energized.

2. The numbers of the digital read-out start the count

down to zero.

3. The turntable motor, oven lamp and fan motor are

energized.

4. The relay RY2 + RY3 are energized alternately within

a 48 seconds time base by the control unit.

5. The top heaters operate through the relay RY3 is

energized. And the high voltage transformer operates

through the relay RY2 is energized.

6. The relationship between the top heating elements and

magnetron operations are as follows.

36 SEC.

(MICRO.)

TOP

HEATERS

OFF

HIGH MIX TOP GRILL mode

26 SEC.

(MICRO.)

TOP

HEATERS

OFF

LOW MIX TOP GRILL mode

Note: The On/Off time ratio does not exactly correspond

to the percentage of microwave power, because

approx. 2 seconds are needed for heating up the

magnetron filament.

7. Upon completion of the selected cooking time, audible

signal sounds and the contacts of relays RY2 + RY3 +

RY6 are opened, then the top heaters, high voltage

transformer, turntable motor and oven lamp are de-

energized. At the end of the convection cycle, if the

cavity air temperature is above 120˚C, the circuit to

RY5 will be maintained (by the thermistor circuit) to

continue operation of the cooling fan motor until the

temperature drops below 104˚C, at which time the

relay will be de0energized, turning off the fan motor.

HIGH MIX BOTTOM GRILL MODE AND LOW MIX BOT-

TOM GRILL MODE

In these modes, the food is cooked by the bottom heater

and the microwave energy. Press the MIX pad three (3)

times for HIGH MIX BOTTOM GRILL mode. Press the MIX

pad four (4) times for LOW MIX BOTTOM GRILL mode.

And then enter the cooking time by pressing the number

pads. When the START pad is pressed, the following

operations occur:

Figure O-5(b) on page 36

1. The relay RY5 + RY6 are energized.

2. The numbers of the digital read-out start the count

down to zero.

3. The turntable motor, oven lamp and fan motor are

R-880F(S)

12 SEC.

MICROWAVE POWER

OFF

= APPROX. 70%

22 SEC.

MICROWAVE POWER

OFF

= APPROX. 50%