Sharp R-1900M Service Manual ▷ View online
R1900M
10 – 1
R1900M
Service Manual
CHAPTER 10.
MICROWAVE MEASUREMENT
After any repair, the microwave oven must be checked for microwave leakage to ensure continued safe operation. BS EN 60335-2-25 specifies that
the maximum permitted leakage with a load of 275 ml is 50 W/m
the maximum permitted leakage with a load of 275 ml is 50 W/m
2
(equivalent to 5 mW/cm
2
) at a distance of 5 cm from the oven.
PREPARATION
The following items are required to carry out this test:
1. A low form of 600 ml beaker made from an electrically non-conductive material, such as glass or plastic, with an inside diameter of approximately
8.5 cm. This must contain 275
± 15 ml of water, at an initial temperature of 20 ± 2°C.
2. A leakage detector which has been calibrated within the preceding 12 months to a stand whose accuracy can be traced to National Physical Lab-
oratory Standards.
Recommended instruments are:
Apollo “XI”
Celtec “A100”
Before commencing the test, check that the leakage detector is functioning and adjusted according to the manufacturer's instructions, and any spac-
ers are fitted to ensure that measurement is taken 5cm from the surface of the oven.
ers are fitted to ensure that measurement is taken 5cm from the surface of the oven.
PROCEDURE
3. Place the beaker containing the water load in the oven cavity at the centre of the turntable. The placing of this standard load in the oven is impor-
tant, not only to protect the oven, but also to ensure that any leakage it is not disguised by too large a load absorbing energy.
4. 2.Close the oven door, and with the power level set to FULL, turn the oven ON with the timer set for a few minutes operation. Should the water
begin to boil before the test has been completed, it should be replaced.
5. 3.As shown in the diagram below, move the probe slowly (not faster than 2.5 cm/sec.);
1) around the edge of the door following the gap
2) across the face of the door
3) across any vents in the oven's sides, rear or top
Whilst the maximum leakage permitted in BS EN 60335-2-25 is 50 W/m
2
(equivalent to 5 mW/cm
2
), it is not normal to detect any significant leakage,
and therefore any detected leakage should be investigated.
Dotted line indicates the path
taken by the leakage detector.
taken by the leakage detector.
R1900M
11 – 1
R1900M
Service Manual
CHAPTER 11.
CIRCUIT DIAGRAMS
[1] Oven Schematic
Figure O-1 Oven Schematic-OFF Condition
Figure O-2 Oven Schematic-Cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1.DOOR CLOSED.
2. “ . ” APPEAR ON DISPLAY.
1.DOOR CLOSED.
2. “ . ” APPEAR ON DISPLAY.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. MANUAL/ REPEAT PAD TOUCHED.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD TOUCHED.
1. DOOR CLOSED.
2. MANUAL/ REPEAT PAD TOUCHED.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD TOUCHED.
NOTE:
indicates components with potential above 250 V.
NEUTRAL
EAR
TH
N
FUSE F10 (1)
COOK
RELAY (1)
MAGNETRON
TEMP. FUSE (1)
MAGNETRON
THERMISTOR (1)
MAGNETRON
THERMISTOR (2)
HUMIDITY
SENSOR
ANT.
SENSOR (1)
3A FUSE
T1
RY1
RY4
D1
F1
F3
F4
H3
H2
H1
G7
G6
G4
G3
G2
G1
G5
F6
F8
F10
F26
F24
F22
F5
F7
F9
F11 F13 F15 F17 F19 F21 F23 F25
F12 F14 F18 F16 F20
D2
D3 D4
D5 D6
D7
D8 D9
D10 D11 D12 D13
A1
E1
A3
C3
C1
E2
OVEN
LAMP
ANTENNA MOT
O
R
(1)
ANTENNA MOT
O
R
(2)
ANT.
SENSOR (2)
MICROWAVE
SENSOR
SECONDARY INTERLOCK
SWITCH (2)
SECONDARY INTERLOCK
SWITCH (2)
EXHAUST
MOTOR
(DC24V)
POWER
TRANSFORMER (1)
H. V.
CAPACITOR (1)
CT1
H. V.
ASYMMETRIC
RECTIFIER (1)
H. V.
RECTIFIER (1)
MAGNETRON
(1)
POWER
TRANSFORMER (2)
H. V.
CAPACITOR (2)
CAPACITOR: 1.00uF
H. V.
ASYMMETRIC
RECTIFIER (2)
H. V.
RECTIFIER (2)
MAGNETRON
(2)
MONIT
OR
SWITCH
(2)
MONIT
OR
SWITCH
(1)
MAGNETRON
TEMP. FUSE (2)
COOK
RELAY (2)
FUSE F10 (2)
OVEN
TEMP.
FUSE
PRIMARY
INTERLOCK
RELAY
DOOR
SENSING
SWITCH
RELAY UNIT
CONTROL UNIT
EM
FF
FM
FM
OL
AM
AM
RY2
RY3
230V - 240V
50Hz
LIVE
L
BLU
GRN/YL
W
BRN
(WEAK
POINT)
(WEAK
POINT)
(WEAK
P
OINT)
(WEAK
P
OINT)
(WEAK
P
OINT)
SWITCHING
POWER
SUPPL
Y
UNIT
Noise
Filter
FAN MOTOR
(DC24V)
EXHAUST FAN
(DC24V)
FA
F
FA
F
NEUTRAL
N
FUSE F10 (1)
COOK
RELAY (1)
MAGNETRON
TEMP. FUSE (1)
MAGNETRON
THERMISTOR (1)
MAGNETRON
THERMISTOR (2)
HUMIDITY
SENSOR
ANT.
SENSOR (1)
3A FUSE
T1
RY1
RY4
D1
F1
F3
F4
H3
H2
H1
G7
G6
G4
G3
G2
G1
G5
F6
F8
F10
F26
F24
F22
F5
F7
F9
F11 F13 F15 F17 F19 F21 F23 F25
F12 F14 F18 F16 F20
D2
D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13
A1
E1
A3
C3
C1
E2
OVEN
LAMP
ANTENNA MOT
O
R
(1)
ANTENNA MOT
O
R
(2)
ANT.
SENSOR (2)
MICROWAVE
SENSOR
SECONDARY INTERLOCK
SWITCH (2)
SECONDARY INTERLOCK
SWITCH (2)
EXHAUST
MOTOR
(DC24V)
POWER
TRANSFORMER (1)
H. V.
CAPACITOR (1)
CT1
H. V.
ASYMMETRIC
RECTIFIER (1)
H. V.
RECTIFIER (1)
MAGNETRON
(1)
POWER
TRANSFORMER (2)
H. V.
CAPACITOR (2)
CAPACITOR: 1.00uF
H. V.
ASYMMETRIC
RECTIFIER (2)
H. V.
RECTIFIER (2)
MAGNETRON
(2)
MONIT
OR
SWITCH
(2)
MONIT
OR
SWITCH
(1)
MAGNETRON
TEMP. FUSE (2)
COOK
RELAY (2)
FUSE F10 (2)
OVEN
TEMP.
FUSE
PRIMARY
INTERLOCK
RELAY
DOOR
SENSING
SWITCH
RELAY UNIT
CONTROL UNIT
EM
FF
FM
FM
OL
AM
AM
RY2
RY3
230V - 240V
50Hz
LIVE
L
BLU
GRN/YL
W
BRN
(WEAK
POINT)
(WEAK
P
OINT)
(WEAK
POINT)
(WEAK
POINT)
(WEAK
POINT)
SWITCHING
POWER
SUPPL
Y
UNIT
Noise
Filter
FAN MOTOR
(DC24V)
EXHAUST FAN
(DC24V)
EAR
TH
FA
F
FA
F
R1900M
11 – 2
[2] Figure S-1. Pictorial Diagram
Magnetron temp.fuse (1)
Magnetron temp.fuse (2)
High voltage
capacitor (1)
Blue
(Blue case)
Blue
(Blue case)
Power
transformer (2)
Red
Red
Gray
Magnetron
thermistor (2)
Magnetron
thermistor (1)
Magnetron (2)
Magnetron (1)
REAR VIEW
Power
transformer (1)
Power
transformer (1)
Crosstape
High voltage
capacitor (2)
Wire holder
White
CPU harness
Red (Red case)
Crosstape
Blue
(Blue case)
Oven lamp socket
Blue
White (White case)
Red (Red case)
Wire holder
LEFT SIDE VIEW
RIGHT SIDE VIEW
Black
Red/Brown
Gray/
White
Brown
Blue/Blue
(Blue case)
Yellow
(Blue case)
Green/Yellow wire
of power supply cord
Earth position of power unit
and door sensing switch
Brown wire of
power supply cord
Blue wire of
power supply cord
Current
transformer
CT1
Wire leads to cook relay
Harness of
exhaust thermistor
Sensor harness
CPU harness
Key unit ribbon cable
Connector CN-F
Connector CN-G
Connector CN-Z
Connector CN-H
Control
unit
Antenna
motor
Weak point for
fan motor
Exhaust
fan motor
Weak point for exhaust fan motor
Weak point for
fan motor
CPU harness
White/Orange/Blue
Red
Brown/Red
Black
White/Gray
Exhaust
thermistor
Oven temp.
fuse
TOP VIEW
CONTROL UNIT
R1900M
11 – 3
Monitor switch (2)
Blue (Blue case)
White (Blue case)
White/Gray (Blue case)
Gray/Gray (Blue case)
Green/Green
Orange
White/White
Brown
Gray
Gray/White
Secondary
interlock
switch (1)
Secondary
interlock
switch (2)
Door sensing
switch
Monitor
switch (1)
Main wire
harness
DC
harness 22
LATCH SWITCHES
Magnetron (1)
FA
FA
F
Power
transformer (1)
Power transformer (2)
High voltage
capacitor (1)
High voltage
rectifier (1)
High voltage rectifier (2)
Asymmetric rectifier (1)
Asymmetric rectifier (2)
High voltage
capacitor (2)
Magnetron (2)
Wiring of high voltage components
F
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