Sharp R-259M (serv.man2) Service Manual ▷ View online
R259(W)
3 – 1
R259(W)
Service Manual
CHAPTER 3.
PRODUCT SPECIFICATIONS
TEM
DESCRIPTION
Power Requirements
230 - 240 Volts
50 Hertz
Single phase, 3 wire earthed
50 Hertz
Single phase, 3 wire earthed
Power Consumption
1.22 kW
Power Output
800 watts nominal of RF microwave energy (measured by method of IEC 60705)
Operating frequency 2450 MHz
Operating frequency 2450 MHz
Case Dimensions
Width 460 mm
Height 275 mm including foot
Depth 380 mm
Height 275 mm including foot
Depth 380 mm
Cooking Cavity Dimensions
Width 319 mm NOTE: Internal capacity is calculated by measuring maximum width, depth and height.
Height 211 mm Actual capacity for holding food is less.
Depth 336 mm
Height 211 mm Actual capacity for holding food is less.
Depth 336 mm
Turntable diameter
272 mm
Control Complement
Touch Control System
Timer (0 - 99 minutes 90 seconds)
Clock (1:00 - 12:59) or (0:00 - 23:59)
Microwave Power for Variable Cooking
Repetition Rate;
HIGH ................................................................ Full power throughout the cooking time
MEDIUM HIGH ................................................................. approx. 70% of FULL Power
MEDIUM ......................................................................... approx. 50% of FULL Power
MEDIUM LOW ................................................................. approx. 30% of FULL Power
LOW ................................................................................ approx. 30% of FULL Power
EXPRESS COOK keys
EXPRESS DEFROST keys
AUTO COOK key
TIME keys
WEIGHT keys
LESS/MORE TIME keys
KITCHEN TIMER/CLOCK SET key
POWER LEVEL key
STOP/CLEAR key
START/AUTO MINUTE key
Timer (0 - 99 minutes 90 seconds)
Clock (1:00 - 12:59) or (0:00 - 23:59)
Microwave Power for Variable Cooking
Repetition Rate;
HIGH ................................................................ Full power throughout the cooking time
MEDIUM HIGH ................................................................. approx. 70% of FULL Power
MEDIUM ......................................................................... approx. 50% of FULL Power
MEDIUM LOW ................................................................. approx. 30% of FULL Power
LOW ................................................................................ approx. 30% of FULL Power
EXPRESS COOK keys
EXPRESS DEFROST keys
AUTO COOK key
TIME keys
WEIGHT keys
LESS/MORE TIME keys
KITCHEN TIMER/CLOCK SET key
POWER LEVEL key
STOP/CLEAR key
START/AUTO MINUTE key
Set Weight (Approx.)
12 kg
R259(W)
4 – 1
R259(W)
Service Manual
CHAPTER 4.
APPEARANCE VIEW
[1] OVEN
1. Ventilation openings
2. Oven lamp
3. Door hinges
4. Door safety latches
5. See through door
6. Door seals sealing surfaces
7. Coupling
8. Control panel
9. Waveguide cover
10. Power supply cord
11. Turntable
12. Roller stay
13. Outer case cabinet
14. Door opening handle
[2] TOUCH CONTROL PANEL
1. DIGITAL DISPLAY
2. TIME keys
3. EXPRESS COOK keys
4. EXPRESS DEFROST keys
5. LESS/MORE TIME keys
6. POWER LEVEL key
7. START/AUTO MINUTE key
8. STOP/CLEAR key
9. KITCHEN TIMER/CLOCK SET key
10.WEIGHT keys
11.AUTO COOK key
NOTE: Some one-touch cooking features such as “AUTO MINUTE” are disabled after three
minutes when the oven is not in use. These features are automatically enabled when
the door is opened and closed or the STOP/ CLEAR pad is pressed.
the door is opened and closed or the STOP/ CLEAR pad is pressed.
11
12
1
10
13
2
7
3
8
14
4
4
5
6
9
1
4
5
6
7
8
9
10
11
2
3
R259(W)
5 – 1
R259(W)
Service Manual
CHAPTER 5.
OPERATION SEQUENCE
[1] OFF CONDITION
Closing the door activates all door interlock switches (1st. latch switch,
2nd. interlock relay control switch).
2nd. interlock relay control switch).
IMPORTANT
When the oven door is closed, the monitor switch contacts (COM-NC)
must be open.
must be open.
When the microwave oven is plugged in a wall outlet, rated voltage is
supplied to the noise filter and the control unit.
supplied to the noise filter and the control unit.
Figure O-1 on page 13-1
1. The display will show flashing “88:88”.
2. To set any programmes or set the clock, you must first touch the
STOP/CLEAR key.
3. “ : “ appears in the display.
[2] MICROWAVE COOKING CONDITION
1. HIGH COOKING
Enter a desired cooking time with the touching TIME keys and start the
oven with touching START key.
oven with touching START key.
Function sequence
Figure O-2 on page 13-1
1. Rated voltage is supplied to the primary winding of the high voltage
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.
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..
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 wave length of 12.24 cm. This energy is channelled
through the waveguide (transport channel) into the oven cavity,
where the food is placed to be cooked.
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) go back to their home position. The circuits to the oven
lamp, high voltage transformer, fan motor and turntable motor are
cut off.
lamp, high voltage transformer, fan motor and turntable motor are
cut off.
5. When the door is opened during a cook cycle, the switches come to
the following condition
The circuits to the high voltage transformer, fan motor, turntable motor
and oven lamp are cut off when the 1st. latch switch and 2nd. interlock
relay control switch are made open.
and oven lamp are cut off when the 1st. latch switch and 2nd. interlock
relay control switch are made open.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by oven door, and
monitors the operation of the 1st. latch switch, the relay (RY1) and
the 2nd. interlock relay (RY2).
monitors the operation of the 1st. latch switch, the relay (RY1) and
the 2nd. interlock relay (RY2).
1) When the oven door is opened during or after the cycle of a
cooking program, the 1st. latch switch and 2nd. interlock relay
control switch must open their contacts first. After that the con-
tacts (COM-NC) of the monitor switch can be closed.
control switch must open their contacts first. After that the con-
tacts (COM-NC) of the monitor switch can be closed.
2) When the oven door is closed, the contacts (COM-NC) of the
monitor switch must be opened. After that the contacts of the
1st. latch switch and 2nd. interlock relay control switch are
closed.
1st. latch switch and 2nd. interlock relay control switch are
closed.
3) When the oven door is opened and the contacts of the 1st. latch
switch, the relay (RY1) and the 2nd. interlock relay (RY2)
remain closed. The fuse (T6.3A) will blow, because the monitor
switch is closed and a short circuit is caused.
remain closed. The fuse (T6.3A) will blow, because the monitor
switch is closed and a short circuit is caused.
2. MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
COOKING
When the microwave oven is preset for variable cooking power, rated
voltage is supplied to the high voltage transformer intermittently within
a 32-second time base through the relay contact which is coupled with
the current-limiting relay. The following levels of microwave power are
given.
voltage is supplied to the high voltage transformer intermittently within
a 32-second time base through the relay contact which is coupled with
the current-limiting relay. The following levels of microwave 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.
are needed for heating up the magnetron filament.
[3] POWER OUTPUT REDUCTION
After 100% power cooking mode is carried out for more than 20 min-
utes, the power out-put is automatically reduced to 70%. Even if the
cooking time is shorter than for 20 minutes, the power output is
reduced to 70% after total cooking time over 20 minutes when the
oven is started in 100% power cooking mode again within 1 minute
and 35 seconds.
utes, the power out-put is automatically reduced to 70%. Even if the
cooking time is shorter than for 20 minutes, the power output is
reduced to 70% after total cooking time over 20 minutes when the
oven is started in 100% power cooking mode again within 1 minute
and 35 seconds.
CONNECTED COMPONENTS
RELAY
Oven lamp, Fan motor, Turntable motor
RY1
High voltage transformer
RY2
CONDITION
SWITCH CONTACT
DURING
COOKING
DOOR OPEN
(NO COOKING)
1st. latch switch
COM-NO
Closed
Open
2nd. interlock relay
control switch
control switch
COM-NO Closed
Open
Monitor switch
COM-NC
Open
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
30P (MEDIUM
LOW)
Approx. 30%
12 sec. ON
10P (LOW)
Approx. 10%
6 sec. ON
R259(W)
6 – 1
R259(W)
Service Manual
CHAPTER 6.
FUNCTION OF IMPOR-
TANT COMPONENTS
[1] DOOR OPEN MECHANISM
The door is opened by pulling the door, refer to the Figure D-1.
Figure D-1. Door Open Mechanism
[2] 1ST. LATCH SWITCH AND 2ND. INTER-
LOCK RELAY CONTROL SWITCH
LOCK RELAY CONTROL 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.
[3] 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 1st
latch switch, the relay (RY1) and the 2nd. interlock relay (RY2) fail
to open, the fuse (T6.3A) blows simultaneously with closing the
contacts (COM-NC) of the monitor switch.
to open, the fuse (T6.3A) blows simultaneously with closing the
contacts (COM-NC) of the monitor switch.
CAUTION: BEFORE REPLACING A FUSE (T6.3A) TEST THE 1ST.
LATCH SWITCH, RELAY (RY1) AND 2ND. INTERLOCK
RELAY (RY2) AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST PROCE-
DURE”.)
RELAY (RY2) AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST PROCE-
DURE”.)
[4] FUSE T6.3A
1. The fuse (T6.3A) blows when the contacts (COM-NO) of the 1 st.
latch switch, the relay (RY1) and the 2nd. interlock relay (RY2)
remain closed with the oven door open and when the monitor
switch closes.
remain closed with the oven door open and when the monitor
switch closes.
2. If the wire harness or electrical components are short-circuited, the
fuse (T6.3A) blows to prevent an electric shock of fire hazard.
[5] HIGH VOLTAGE FUSE
The high voltage fuse blows when the high voltage rectifier or the mag-
netron is shorted.
netron is shorted.
[6] TEMPERATURE FUSE 150C (OVEN)
The temperature fuse located on the top of the oven cavity is designed
to prevent damage to the oven if the foods in the oven catch fire due to
over heating produced by improper setting of cook time or failure of
control unit. Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are reached
within the oven cavity, the temperature fuse will open at 150
to prevent damage to the oven if the foods in the oven catch fire due to
over heating produced by improper setting of cook time or failure of
control unit. Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are reached
within the oven cavity, the temperature fuse will open at 150
°C, caus-
ing the oven to shut down. The defective temperature fuse must be
replaced with a new one.
replaced with a new one.
[7] TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to rotate the
turntable.
turntable.
[8] FAN MOTOR
The fan motor drives a blade which draws external cool air. This cool
air is directed through the air vanes surrounding the magnetron and
cools the magnetron. This air is channelled through the oven cavity to
remove steam and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven cavity.
air is directed through the air vanes surrounding the magnetron and
cools the magnetron. This air is channelled through the oven cavity to
remove steam and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven cavity.
[9] NOISE FILTER
The noise filter prevents the radio frequency interference that might
flow back in the power circuit.
flow back in the power circuit.
Latch Heads
Latch Hook
Door
2nd. Interlock Relay
Control Switch
Control Switch
1st. Latch Switch
Monitor Switch
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