R-899SL (serv.man5). Operation Sequence — Sharp Home Appliance Service Manual (repair manual)

Model
R-899SL (serv.man5)
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4 Few pages! See other manuals at the bottom of the first or last page.
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Document
Service Manual
Brand
Device
Home Appliance / Microwave Oven / Operation Sequence
File
r-899sl-sm5.pdf
Date

View Sharp R-899SL (serv.man5) Service Manual online

R899(WH)
5 – 1
R899(WH)
Service Manual
 
CHAPTER 5. 
OPERATION SEQUENCE
[1] OFF CONDITION
Closing the door activates the monitored latch switch and the stop
switch.
IMPORTANT
When the oven door is closed, the contacts COM-NC of the moni-
tor switch must be open. When the microwave oven is plugged in
a wall outlet (230 - 240V / 50Hz), the line voltage is supplied to the
noise filter.
                                            Figure O-1 on page 13-1 
1. The control unit is not energized. The display shows nothing (Fig.
O-1 (a)).
2. Open the door. The contacts (COM-NC) of the monitored latch
switch are closed and the control unit is energized. Then contacts
of relays RY1 and RY5 are closed, and the oven lamp will light and
the display will show “ENERGY SAVE MODE TO CANCEL
ENERGY SAVE MODE SET THE CLOCK” (Fig. O-1(b)).
3. Close the door. The contacts (COM-NC) of the monitored latch
switch are opened and the contacts of relay RY1 are opened and
the oven lamp will be turned off. The display will show “ . 0". (Fig.
O-1(c)).
NOTE: Energy save mode
1) If the oven has not been used for more than 3 minutes, the
contacts of the relay RY5 will be opened and the control
unit will be not energized. Open and close the door, the
control unit will resume.
2) If the clock is set, this energy save mode does not work.
[2] MICROWAVE COOKING CONDITION
1. HIGH COOKING
Rotate the COOKING MODE dial to the
micro setting. And press
the MICROWAVE POWER LEVEL button once. And enter the cooking
time by rotating the TIME/WEIGHT dial. And start the oven by pressing
START button.
Function sequence 
                           Figure O-2 on page 13-2
1. The line voltage is supplied to the primary winding of the high volt-
age transformer. The voltage is converted to about 3.3 volts A.C.
output on the filament winding and high voltage of approximately
2000 volts A.C. on the secondary winding.
2. The filament winding voltage (3.3 volts) heats the magnetron fila-
ment and the high voltage (2000 volts) is sent to the voltage dou-
bling circuit, where it is doubled to negative voltage of
approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the magnetron gen-
erates a wavelength of 12.24cm. This energy is channelled through
the waveguide (transport channel) into the oven cavity, where the
food is placed to be cooked.
4. When the cooking time is up, a signal tone is heard and the relays
RY1 + RY2 + RY6 go back to their home position. The circuits to
the oven lamp, high voltage transformer, fan motor and turntable
motor are cut off.
5. When the oven door is opened during a cooking cycle, the switches
come to the following condition.
The circuit to the high voltage transformer is cut off when the contacts
of relay RY2, and the contacts (COM-NO) of the monitored latch
switch and monitor switch are made open. The circuit to the fan motor
is cut off when the relay RY6 is made open. The circuit to the turntable
motor is cut off when the contacts (COM-NO) of the monitored latch
switch are made open. The relay RY2 and RY6 are made open when
the door is opened. The oven lamp remains on even if the oven door is
opened after the cooking cycle has been interrupted, because the
relay RY1 stays closed. Shown in the display is remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by the oven door,
and monitors the operation of the monitored latch switch.
1) When the oven door is opened during or after the cycle of a
cooking program, the monitored latch switch and stop switch
must open their contacts (COM-NO) first. After that the contacts
(COM-NC) of the monitor switch and monitored latch can be
closed.
2) When the oven door is closed, the contacts (COM-NC) of the
monitor switch SW3 must be opened and the contacts (COM-
NO) of monitor switch must be closed. After that the contacts
(COM-NO) of the monitored latch switch and the stop switch are
made closed, and the contacts (COM-NC) of the monitored
latch switch are made open.
3) When the oven door is opened and the contacts (COM-NO) of
the monitored latch switch remain closed, the fuse F8A will
blow. Because the relay RY1 and monitor switch are closed and
a short circuit is caused.
2. MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
When the microwave oven is preset for variable cooking power, the
line voltage is supplied to the high voltage transformer intermittently
within a 32-second time base through the relay contact which is cou-
pled with the current-limiting relay RY2. The following levels of micro-
wave power are given.
SETTING;
NOTE: The ON/OFF time ratio does not exactly correspond to the
percentage of microwave power, because approx. 3 seconds
are needed for heating up the magnetron filament.
CONNECTED COMPONENTS
RELAY
Oven lamp, Turntable motor 
RY1
High voltage transformer 
RY2
Fan motor, 
RY6
          CONDITION
SWITCH CONTACT 
DURING 
COOKING
DOOR OPEN 
(NO COOKING)
Monitored latch 
switch 
COM-NO
COM-NC 
Closed
Opened 
Opened
Closed
Stop switch   
COM-NO 
Closed 
Opened
Monitor switch        
COM-NO
COM-NC 
Closed
Opened   
Opened
Closed
100P (HIGH)
32 sec. ON
70P
(MEDIUM HIGH)
Approx. 70%
100%
24 sec. ON
8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
50P
(MEDIUM)
Approx. 50%
18 sec. ON
50P
(MEDIUM LOW)
Approx. 30%
12 sec. ON
10P (LOW)
Approx. 10%
6 sec. ON
R899(WH)
5 – 2
[3] GRILL COOKING CONDITION
1. TOP GRILL (Figure O-3)
In this condition the food is cooked by the top grill heating element.
Rotate the COOKING MODE dial to 
TOP GRILL setting. And
enter the desired cooking time by rotating the TIME/WEIGHT dial.
When the START button is pressed, the following operations occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor and turntable motor are ener-
gized.
3. The relay RY3 is energized and the main supply voltage is applied
to the top grill heating element.
4. Now, the food is cooked by the top grill heating element.
2. BOTTOM GRILL (Figure O-3b)
In this condition the food is cooked by bottom grill heating element
energy. Rotate the COOKING MODE dial to 
BOTTOM GRILL set-
ting. And enter the desired cooking time by rotating the TIME/WEIGHT
dial. When the START button is pressed, the following operations
occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor and turntable motor are ener-
gized.
3. The relay RY4 is energized and the main supply voltage is applied
to the bottom grill heating element.
4. Now, the food is cooked by the bottom grill heating element.
3. TOP AND BOTTOM GRILLS (Figure O-3c)
In this condition the food is cooked by top and bottom grill heating ele-
ments energy. Rotate the COOKING MODE dial to 
TOP AND
BOTTOM GRILLS setting. And enter the desired cooking time by rotat-
ing the TIME/WEIGHT dial. When the START button is pressed, the
following operations occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor and turntable motor are ener-
gized.
3. The relay RY4 is energized and the main supply voltage is applied
to the bottom grill heating element.
4. The relay RY3 is energized and the main supply voltage is applied
to the top grill heating element. 
5. Now, the food is cooked by the top and bottom grill heating ele-
ments.
[4] CONVECTION COOKING CONDITION
1. PRE-HEATING (Figure O-4)
Rotate the COOKING MODE dial to the 
convection setting. And
programme the desired convection temperature by touching CON-
VECTION button. When the START button is touched, the following
operations occur:
1. The coil shut-off relays RY1 and RY6 are energized, the oven lamp,
cooling fan motor and turntable motor are turned on.
2. The coil shut-off relays RY3 and RY4 are energized by control unit
and the main supply voltage is added to the top and bottom heating
elements.
3. When the oven temperature reaches the selected pre-heat temper-
ature, the following operations occur:
1) The coil shut-off relays RY3 and RY4 are energized by control
unit temperature circuit and thermistor, opening the circuit to the
top and bottom grill heating elements.
2) The oven will continue to function for 30 minutes, turning the top
and bottom heating elements on and off, as needed to maintain
the selected pre-heat temperature. The oven will shut-down
completely after 30 minutes.
2. CONVECTION COOKING (Figure O-4)
When the pre-heat temperature is reached, a beep signal will sound
indicating that the holding the temperature has been reached in the
oven cavity. Open the door and place the food to cooked in the oven.
Rotate the COOKING MODE dial to the 
convection setting. And
enter the cooking time by rotating the TIME/WEIGHT dial. And select
the desired cooking temperature by pressing the CONVECTION but-
ton. When the START button is pressed, the following operations
occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor, turntable motor and convection
motor are energized.
NOTE: When the convection temperature 40
°C is selected, the con-
vection motor is not energized.
3. The relays RY3 and RY4 are energized (if the cavity temperature is
lower than selected temperature) and the main supply voltage is
applied to the top and bottom heating elements to return to the
selected cooking temperature.
4. Upon completion of the cooking time, the audible signal will sound,
and the oven lamp, turntable motor, cooling fan motor, convection
motor, top and bottom heating elements are de-energized. At the
end of convection cycle, if the cavity air temperature rise above
120
°C, the circuit to the relay RY6 will be maintained (by the ther-
mistor circuit) to continue operation of the cooling fan motor until
temperature drops below 105
°C, at that time the relay RY6 will be
de-energized, turning off the fan motor.
[5] COMBI COOKING CONDITION
1. MICROWAVE AND CONVECTION (Figure O-5a)
Rotate the COOKING MODE dial to 
COMBI 1 setting. And
enter the desired cooking time by rotating the TIME/WEIGHT dial. And
press MICROWAVE POWER LEVEL button to set the desired micro-
wave power. And press the CONVECTION button to set the cooking
temperature. When the START button is pressed, the following opera-
tions occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor, turntable motor and convection
motor are energized.
3. The relay RY3 will be energized and the main supply voltage is
applied to the top grill heating element.
4. The relay RY4 is energized (if the cavity temperature is lower than
selected temperature) and the main supply voltage is applied to the
bottom heating element.
5. The relay RY2 is energized and the microwave energy is generated
by magnetron.
6. Now, the food is cooked by microwave and convection energy
simultaneously.
2. MICROWAVE AND TOP GRILL (Figure O-5b)
Rotate the COOKING MODE dial to 
COMBI 2 setting. And enter
the desired cooking time by rotating the TIME/WEIGHT dial. And press
MICROWAVE POWER LEVEL button to set the desired microwave
power. When the START button is pressed, the following operations
occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor and turntable motor are ener-
gized.
R899(WH)
5 – 3
3. The relay RY3 is energized and the main supply voltage is applied
to the top grill heating element.
4. The relay RY2 is energized and the microwave energy is generated
by magnetron.
5. Now, the food is cooked by microwave and top grill simultaneously.
3. MICROWAVE AND BOTTOM GRILL (Figure O-5c)
Rotate the COOKING MODE dial to 
COMBI 3 setting. And enter
the desired cooking time by rotating the TIME/WEIGHT dial. And press
MICROWAVE POWER LEVEL button to set the desired microwave
power. When the START button is pressed, the following operations
occur:
1. The numbers on the digital readout start the count down to zero.
2. The oven lamp, cooling fan motor and turntable motor are ener-
gized.
3. The relay RY4 is energized and the main supply voltage is applied
to the bottom grill heating element.
4. The relay RY2 is energized and the microwave energy is generated
by magnetron.
5. Now, the food is cooked by microwave and bottom grill simulta-
neously.
[6] ON/OFF TIME RATIO
In grill cooking, convection cooking or combi cooking, the top heater,
bottom heater or magnetron operate within a 54 second time base.
The following table is the ON / OFF time ratio at each power output of
the top heaters, bottom heater or magnetron.
[7] AUTO POWER CONTROL OPERATION
The magnetron, top or bottom heating elements, the fan motor or the convection motor will operate in accordance with following specification.
1. OUTPUT POWER CONTROL (MANUAL COOK)
2. OUTPUT POWER CONTROL (AUTO COOK)
POWER OUTPUT
ON TIME
OFF TIME
100%
54 sec.
0 sec.
90%
49 sec.
5 sec.
80%
45 sec.
9 sec.
70%
40 sec.
14 sec.
60%
36 sec.
18 sec.
50%
29 sec.
25 sec.
40%
24 sec.
30 sec.
30%
18 sec.
36 sec.
20%
13 sec.
41 sec.
10%
9 sec.
45 sec.
OPERATION MODE
DEVICE
POWER CONTROL
MICROWAVE (100%) 
SINGLE OPERATION
Microwave
100% 20min, then 70%
TOP GRILL (100%) 
SINGLE OPERATION
Top heater
100% 15min, then 50%
BOTTOM GRILL (100%) 
SINGLE OPERATION
Bottom heater
100% 15min, then 50%
TOP(100%)/BOTTOM(100%)
COMBI OPERATION
Top heater
100% 6min then 70% and 70% 9min then 50%
Bottom heater
100% 6min then 70% and 70% 9min then 50%
MICRO(100%)/TOP GRILL(100%)
COMBI OPERATION
Microwave
100% 20min, then 70%
Top heater
100% 15min, then 50%
MICRO(70 - 10%)/TOP GRILL(100%)
COMBI OPERATION
Microwave
-
Top heater
100% 15min, then 50%
MICRO(100%)/BOTTOM GRILL(100%)
COMBI OPERATION
Microwave
100% 20min, then 70%
Bottom heater
100% 15min, then 50%
MICRO(70 - 10%)/BOTTOM GRILL(100%)
COMBI OPERATION
Microwave
-
Bottom heater
100% 15min, then 50%
Repeat Cook
Microwave
Top heater
Bottom heater
In case same cooking mode is repeated within 1min 15sec (including stop, end), 
oven calculates total cooking time and reduce the power level.
OPERATION MODE
DEVICE
POWER CONTROL
Repeat Auto Cook
Microwave
The power level is not reduced 1 time cooking. But only in case same menu is 
repeated within 1min 15sec, the power level of micro and grill is reduced from 
100% to 70% in 20mins after starting of last cooking. (Even if the time of the last 
cooking is longer than 20mins, the power level isn't reduced on the last cooking, 
and it is reduced from the beginning of the next cooking.) However, in time calcu-
lated from the start of the 1st cooking, even if the Cook mode changed, when rep-
etition cooking of the menu with which 100% of top & bottom heaters continues 
are performed, as shown in the following table, the power down of the cooking of 
the 2nd henceforth is carried out. (The 1st cooking is not applied)
R899(WH)
5 – 4
3. COOLING FAN OPERATION
4. CONVECTION POWER SETTING
4.1. PREHEATING
4.2. CONVECTION
4.3. COMBI-1 (Micro + Conv)
NOTE:
✩The oven temp was checked by the thermometer when each stage is started.
If the oven temp is same or higher than 105
°C, the oven was judged as "with preheating".
When the oven temp is lower than 105
Micro and Top heating element can't be on at the same time.
OPERATION MODE
DEVICE
POWER CONTROL
PREHEAT
Cooling
60% 
CONV. (OVEN)
Cooling fan
60% 60 min. then 100%
Others
Cooling fan
100%
After cooking
Cooling fan
A cooling fan continues the rotation when Oven temperature is more than 120
°C. 
Then, it stops when it is less than 105
°C
Indication
NOW COOLING is indicated during the cooling fan movement after operation is 
finished. (It isn't indicated during a fan movement to stop on the way.)
TEMP
 250
°C, 230°C, 220°C, 200°C, 180°C, 160°C, 130°C, 100°C, 70°C, 40°C
HEATING ELEMENT 
TOP 100%
BOTTOM
100%
COOLING FAN 
60%
CONV. FAN 
0%
TEMP
250
°C
230
°C
220
°C
200
°C
180
°C
160
°C
130
°C 100°C
70
°C
40
°C
✩WITHOUT PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
100%
90%
80%
70%
70%
60%
50%
40%
30%
20%
✩WITH PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
90%
70%
60%
50%
50%
50%
50%
40%
30%
20%
COOLING FAN
60% 60min, then 100%
CONV. FAN
100%
0%
TEMP
250
°C
230
°C
220
°C
200
°C
180
°C
160
°C
130
°C
100
°C
70
°C
40
°C
✩WITHOUT PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
100%
90%
80%
70%
70%
60%
50%
40%
30%
20%
✩WITH PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
90%
70%
60%
50%
50%
50%
50%
40%
30%
20%
MICRO
10%, 30%, 50%
COOLING FAN
100%
CONV. FAN
100%
0%
R899(WH)
5 – 4
3. COOLING FAN OPERATION
4. CONVECTION POWER SETTING
4.1. PREHEATING
4.2. CONVECTION
4.3. COMBI-1 (Micro + Conv)
NOTE:
✩The oven temp was checked by the thermometer when each stage is started.
If the oven temp is same or higher than 105
°C, the oven was judged as "with preheating".
When the oven temp is lower than 105
Micro and Top heating element can't be on at the same time.
OPERATION MODE
DEVICE
POWER CONTROL
PREHEAT
Cooling
60% 
CONV. (OVEN)
Cooling fan
60% 60 min. then 100%
Others
Cooling fan
100%
After cooking
Cooling fan
A cooling fan continues the rotation when Oven temperature is more than 120
°C. 
Then, it stops when it is less than 105
°C
Indication
NOW COOLING is indicated during the cooling fan movement after operation is 
finished. (It isn't indicated during a fan movement to stop on the way.)
TEMP
 250
°C, 230°C, 220°C, 200°C, 180°C, 160°C, 130°C, 100°C, 70°C, 40°C
HEATING ELEMENT 
TOP 100%
BOTTOM
100%
COOLING FAN 
60%
CONV. FAN 
0%
TEMP
250
°C
230
°C
220
°C
200
°C
180
°C
160
°C
130
°C 100°C
70
°C
40
°C
✩WITHOUT PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
100%
90%
80%
70%
70%
60%
50%
40%
30%
20%
✩WITH PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
90%
70%
60%
50%
50%
50%
50%
40%
30%
20%
COOLING FAN
60% 60min, then 100%
CONV. FAN
100%
0%
TEMP
250
°C
230
°C
220
°C
200
°C
180
°C
160
°C
130
°C
100
°C
70
°C
40
°C
✩WITHOUT PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
100%
90%
80%
70%
70%
60%
50%
40%
30%
20%
✩WITH PREHEATING
HEATING 
ELEMENT
TOP
50%
40%
40%
30%
20%
10%
10%
10%
10%
10%
BOTTOM
90%
70%
60%
50%
50%
50%
50%
40%
30%
20%
MICRO
10%, 30%, 50%
COOLING FAN
100%
CONV. FAN
100%
0%

Download Sharp R-899SL (serv.man5) Service Manual (Repair Manual)

Here you can view online or download Sharp R-899SL (serv.man5) Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Sharp R-899SL (serv.man5) Microwave Oven. Information contained in Sharp R-899SL (serv.man5) service manual (repair manual) typically includes:

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