Sharp R-734 (serv.man4) Service Manual ▷ View online
R-734 - 29
TEST DATA AT A GLANCE
PARTS
SYMBOL
VALUE / DATA
Special fuse
F1
20A / 250V
Fuse
F2
F 8A / 250V
Thermal cut-out (MAG.)
TC1
125
°
C Off
Thermal cut-out (OVEN)
TC2
145
°
C Off / 115˚C On
Grill heating element
GH
Approx. 56
Ω
/ Insulation resistance > 10 M
Ω
Oven lamp
OL
240–250 V 25W
High voltage capacitor
C
1.07
µ
F AC 2100V
Filament < 1
Ω
Magnetron
MG
Filament – chassis
∞
ohm.
Filament winding < 1
Ω
High voltage transformer
T
Secondary winding Approx. 130
Ω
Primary winding Approx. 2
Ω
WARNING: DISCONNECT THE PLUG WHEN MEASURING RESISTANCE.
6. Release two (2) pins of door panel from two (2) holes
upper and lower oven hinges by lifting up.
7. Now, door sub assembly is free from oven cavity.
8. Remove the six (6) screws holding the door panel to the
8. Remove the six (6) screws holding the door panel to the
door frame.
9. Now, door panel is free.
10.Slide latch head upward and remove it from door
10.Slide latch head upward and remove it from door
frame, releasing latch spring from door frame and
latch head.
latch head.
11.Now, latch head and latch spring are free.
12.Remove the one (1) screw holding the glass stopper to
12.Remove the one (1) screw holding the glass stopper to
the door frame.
13.Remove the glass stopper from the door frame.
14.Slide the front door glass upwards and then right-
14.Slide the front door glass upwards and then right-
wards.
15.Remove the door glass from the door frame.
16.Remove the handle covers A and B from the door
16.Remove the handle covers A and B from the door
frame.
17.Now, the door frame is free
RE-INSTALL
1. Re-install the front door glass to the door frame as
1. Re-install the front door glass to the door frame as
follows.
1) Insert the upper edge of the front door glass into the
1) Insert the upper edge of the front door glass into the
door frame.
2) Slide the front door glass downwards into the door
frame and then leftwards.
3) Re-install the glass stopper to the door frame with
one (1) screw.
2. Re-install the handle covers A and B to the door frame.
3. Re-install the latch spring to the latch head. Re-install
3. Re-install the latch spring to the latch head. Re-install
the latch spring to the door frame. Re-install latch head
to door frame.
to door frame.
4. Fit the door panel to the door frame with six (6) screws.
5. Insert two (2) pins of door panel on two (2) holes of
5. Insert two (2) pins of door panel on two (2) holes of
upper and lower oven hinges.
6. Re-install choke cover to door panel.
Note: After any service to the door;
(A) Make sure that the monitor switch, monitored
latch switch and stop switch are operating prop-
erly.
erly.
Figure C-9. Door Replacement
NOTE: When carrying out any repair to the door,
do not bend or warp the slit choke (tabs on
the door panel assembly) to prevent
microwave leakage.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
PIN
PIN
LOWER
OVEN HINGE
OVEN HINGE
UPPER
OVEN HINGE
OVEN HINGE
LOWER
OVEN HINGE
OVEN HINGE
CHOKE COVER
DOOR
PANEL
PANEL
DOOR SUB
ASSEMBLY
ASSEMBLY
SLIT CHOKE
R-734 - 30
MICROWAVE MEASUREMENT
After adjustment of door latch switches, monitor switch
and door are completed individually or collectively, the
following leakage test must be performed with a survey
instrument and it must be confirmed that the result meets
the requirements of the performance standard for micro-
wave oven.
and door are completed individually or collectively, the
following leakage test must be performed with a survey
instrument and it must be confirmed that the result meets
the requirements of the performance standard for micro-
wave oven.
REQUIREMENT
The safety switch must prevent microwave radiation emis-
sion in excess of 5mW/cm
sion in excess of 5mW/cm
2
at any point 5cm or more from
external surface of the oven.
PREPARATION FOR TESTING:
Before beginning the actual test for leakage, proceed as
follows;
1. Make sure that the test instrument is operating nor-
follows;
1. Make sure that the test instrument is operating nor-
mally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement
for instrumentations as prescribed by the performance
standard for microwave ovens must be used for test-
ing.
Important:
Survey instruments that comply with the requirement
for instrumentations as prescribed by the performance
standard for microwave ovens must be used for test-
ing.
Recommended instruments are:
NARDA 8100
NARDA 8200
HOLADAY HI 1500
SIMPSON 380M
NARDA 8100
NARDA 8200
HOLADAY HI 1500
SIMPSON 380M
2. Place the oven tray into the oven cavity.
3. Place the load of 275
3. Place the load of 275
±
15ml of water initially at 20
±
5˚C in the centre of the oven tray. The water
container should be a low form of 600 ml beaker with
inside diameter of approx. 8.5cm and made of an
electrically non-conductive material such as glass
or plastic.
The placing of this standard load in the oven is impor-
tant not only to protect the oven, but also to insure that
any leakage is measured accurately.
inside diameter of approx. 8.5cm and made of an
electrically non-conductive material such as glass
or plastic.
The placing of this standard load in the oven is impor-
tant not only to protect the oven, but also to insure that
any leakage is measured accurately.
4. Close the door and turn the oven ON with the timer set
for several minutes. If the water begins to boil before
the survey is completed, replace it with 275ml of cool
water.
the survey is completed, replace it with 275ml of cool
water.
5. Move the probe slowly (not faster that 2.5cm/sec.)
along the gap.
6. The microwave radiation emission should be meas-
ured at any point of 5cm or more from the external
surface of the oven.
surface of the oven.
mW cm
2
mW cm
2
Microwave leakage measurement at 5 cm distance
R-734 - 31
Figure O-2 Oven Schematic-Microwave cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Cooking mode at microwave.
4. START button pressed.
1. Door closed.
2. Cooking time set.
3. Cooking mode at microwave.
4. START button pressed.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking mode at microwave.
3. Timer at zero.
1. Door closed.
2. Cooking mode at microwave.
3. Timer at zero.
Figure O-1. Oven Schematic-OFF Condition
Note: " " Indicates components with potential above 250 V.
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GH: GRILL HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
C:
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
A5
RY3
COM.
COM.
A3
A1
B2
B1
SW3:
STOP SWITCH
STOP SWITCH
SW1:
MONITORED
LATCH SWITCH
MONITORED
LATCH SWITCH
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW2:
MONITOR
SWITCH
MONITOR
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: SPECIALFUSE 20A
F2:
FUSE
F8A
FUSE
F8A
NOISE FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY1
RY2
FM
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GH: GRILL HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
C:
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
A5
RY3
COM.
COM.
A3
A1
B2
B1
SW3:
STOP SWITCH
STOP SWITCH
SW1:
MONITORED
LATCH SWITCH
MONITORED
LATCH SWITCH
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW2:
MONITOR
SWITCH
MONITOR
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F2:
FUSE
F8A
FUSE
F8A
NOISE FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY1
RY2
FM
F1: SPECIALFUSE 20A
SCHEMATIC DIAGRAMS
R-734 - 32
Figure O-3. Oven Schematic-Grill cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Cooking mode at Grill.
4. START button pressed.
1. Door closed.
2. Cooking time set.
3. Cooking mode at Grill.
4. START button pressed.
Figure O-4. Oven Schematic-Dual Cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Cooking mode at Dual Grill.
4. START button pressed.
1. Door closed.
2. Cooking time set.
3. Cooking mode at Dual Grill.
4. START button pressed.
Note: " " Indicates components with potential above 250 V.
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GH: GRILL HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
C:
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
A5
RY3
COM.
COM.
A3
A1
B2
B1
SW3:
STOP SWITCH
STOP SWITCH
SW1:
MONITORED
LATCH SWITCH
MONITORED
LATCH SWITCH
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW2:
MONITOR
SWITCH
MONITOR
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F2:
FUSE
F8A
FUSE
F8A
NOISE FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY1
RY2
FM
F1: SPECIALFUSE 20A
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GH: GRILL HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
C:
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
A5
RY3
COM.
COM.
A3
A1
B2
B1
SW3:
STOP SWITCH
STOP SWITCH
SW1:
MONITORED
LATCH SWITCH
MONITORED
LATCH SWITCH
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW2:
MONITOR
SWITCH
MONITOR
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F2:
FUSE
F8A
FUSE
F8A
NOISE FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY1
RY2
FM
F1: SPECIALFUSE 20A
SCHEMATIC DIAGRAMS
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