Sharp R-754M (serv.man4) Service Manual ▷ View online
R-754M - 25
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
Pin
Pin
Upper oven hinge
Lower
oven
hinge
oven
hinge
Lower oven
hinge
hinge
Choke cover
Door panel
Slit choke
Slit choke
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
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.
R-754M - 26
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
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
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
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
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 Laboratory Stand-
ards.
can be traced to National Physical Laboratory Stand-
ards.
Recommended instruments are:
Apollo "XI"
Celtec "A100"
Celtec "A100"
Before commencing the test, check that the leakage
detector is functioning and adjusted according to the
manufacturer's instructions, and any spacers are fitted to
ensure that measurement is taken 5cm from the surface of
the oven.
detector is functioning and adjusted according to the
manufacturer's instructions, and any spacers are fitted to
ensure that measurement is taken 5cm from the surface of
the oven.
PROCEDURE
1. 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 important, not only to
protect the oven, but also to ensure that any leakage
it is not disguised by too large a load absorbing energy.
standard load in the oven is important, not only to
protect the oven, but also to ensure that any leakage
it is not disguised by too large a load absorbing energy.
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.
minutes operation. Should the water begin to boil
before the test has been completed, it should be
replaced.
3. As shown in the diagram below, move the probe slowly
(not faster than 2.5 cm/sec.);-
a) around the edge of the door following the gap
b) across the face of the door
c) across any vents in the oven's sides, rear or top
b) across the face of the door
c) 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 detec-
tor.
tor.
R-754M - 27
Figure O-2 Oven Schematic-Microwave cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Microwave power level set.
4. START key pressed.
1. Door closed.
2. Cooking time set.
3. Microwave power level set.
4. START key 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
GRILL HEATING ELEMENT
H.V. RECTIFIER
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
RY3
COM.
COM.
A3
A1
B2
B1
STOP SWITCH
MONITORED
LATCH SWITCH
LATCH SWITCH
MG.
THERMAL
CUT-OUT
125˚C
THERMAL
CUT-OUT
125˚C
OVEN
THERMAL
CUT-OUT
145˚C
THERMAL
CUT-OUT
145˚C
MONITOR
SWITCH
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
SPECIALFUSE 20A
FUSE
F8A
NOISE FILTER
L
N
230-240V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
COM.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY2
RY1
FM
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GRILL HEATING ELEMENT
H.V. RECTIFIER
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
RY3
COM.
COM.
A3
A1
B2
B1
STOP SWITCH
MONITORED
LATCH SWITCH
LATCH SWITCH
MG.
THERMAL
CUT-OUT
125˚C
THERMAL
CUT-OUT
125˚C
OVEN
THERMAL
CUT-OUT
145˚C
THERMAL
CUT-OUT
145˚C
MONITOR
SWITCH
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
SPECIALFUSE 20A
FUSE
F8A
NOISE FILTER
L
N
230-240V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
COM.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY2
RY1
FM
SCHEMATIC DIAGRAMS
R-754M - 28
Figure O-3. Oven Schematic-Grill cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Grill key pressed.
4. START key pressed.
1. Door closed.
2. Cooking time set.
3. Grill key pressed.
4. START key pressed.
Figure O-4. Oven Schematic-Dual Cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. Door closed.
2. Cooking time set.
3. Dual Gril key pressedl.
4. START key pressed.
1. Door closed.
2. Cooking time set.
3. Dual Gril key pressedl.
4. START key pressed.
Note: " " Indicates components with potential above 250 V.
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GRILL HEATING ELEMENT
H.V. RECTIFIER
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
RY3
COM.
COM.
A3
A1
B2
B1
STOP SWITCH
MONITORED
LATCH SWITCH
LATCH SWITCH
MG.
THERMAL
CUT-OUT
125˚C
THERMAL
CUT-OUT
125˚C
OVEN
THERMAL
CUT-OUT
145˚C
THERMAL
CUT-OUT
145˚C
MONITOR
SWITCH
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
SPECIALFUSE 20A
FUSE
F8A
NOISE FILTER
L
N
230-240V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
COM.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY2
RY1
FM
OL
TTM
OVEN LAMP
FAN MOTOR
TURNTABLE MOTOR
GRILL HEATING ELEMENT
H.V. RECTIFIER
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
CAPACITOR
1.07
µ
F
AC2100V
CONTROL UNIT
RY3
COM.
COM.
A3
A1
B2
B1
STOP SWITCH
MONITORED
LATCH SWITCH
LATCH SWITCH
MG.
THERMAL
CUT-OUT
125˚C
THERMAL
CUT-OUT
125˚C
OVEN
THERMAL
CUT-OUT
145˚C
THERMAL
CUT-OUT
145˚C
MONITOR
SWITCH
SWITCH
0.0047
µ
/ 250V
0.0047
µ
/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
SPECIALFUSE 20A
FUSE
F8A
NOISE FILTER
L
N
230-240V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
N.C.
N.O.
N.O.
COM.
N.O.
N.O.
N.O.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY2
RY1
FM
SCHEMATIC DIAGRAMS
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