Sharp R-852 (serv.man2) Service Manual ▷ View online
R-852 - 31
screws.
6. Located door panel hinge pins into cavity hinge loca-
tion holes.
7. Re-install choke cover to door panel by clipping into
position.
Note: After any service to the door;
(A) Make sure that the monitor switch, monitored
latch switch and stop switch are operating prop-
erly. (Refer to chapter "Test Procedures".).
erly. (Refer to chapter "Test Procedures".).
(B) An approved microwave survey meter should be
used to assure compliance with proper micro-
wave radiation emission limitation standards.
(Refer to Microwave Measurement Procedure.)
wave radiation emission limitation standards.
(Refer to Microwave Measurement Procedure.)
After any service, make sure of the following :
1. Door latch heads smoothly catch latch hook through
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through centre of
latch hole.
latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approved microwave survey meter. (Refer to Micro-
wave Measurement Procedure.)
wave Measurement Procedure.)
Note:
The door on a microwave oven is designed to act
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or light-
tight. Therefore, occasional appearance of mois-
ture, light or sensing of gentle warm air movement
around oven door is not abnormal and do not of
themselves, indicate a leakage of microwave en-
ergy from oven cavity.
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or light-
tight. Therefore, occasional appearance of mois-
ture, light or sensing of gentle warm air movement
around oven door is not abnormal and do not of
themselves, indicate a leakage of microwave en-
ergy from oven cavity.
Figure C-8. Door Replacement
9. Release door panel from six (6) tabs of door frame by
sliding door panel upward.
10.Now, door panel is free.
11.Slide latch head upward and remove it from door
11.Slide latch head upward and remove it from door
frame with releasing latch spring from door frame and
latch head.
latch head.
12.Now, latch head and latch spring are free.
13.Remove the two (2) screws holding the glass stopper
13.Remove the two (2) screws holding the glass stopper
to the door frame.
14.Remove the glass stopper from the door frame.
15.Slide the front door glass leftwards and then slide
15.Slide the front door glass leftwards and then slide
upwards to release the tabs holding it.
16.Now, the front door glass 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.
a) Insert the upper edge of the front door glass into the
a) Insert the upper edge of the front door glass into the
six (6) tabs of the door frame.
b) Slide the front door glass downwards and insert the
lower edge of the front door glass into the six (6)
tabs of the door frame.
tabs of the door frame.
c) Slide the front door glass rightwards and insert the
right edge of the front door glass into the one (1) tab
of the door frame.
of the door frame.
2. Re-install the glass stopper to the door frame as
follows.
a) Re-install the glass stopper to the door frame so
a) Re-install the glass stopper to the door frame so
that the two (2) holes of the glass stopper meet the
two (2) pins of the door frame.
two (2) pins of the door frame.
b) Hold the glass stopper to the door frame with the
two (2) screws.
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. Re-install door panel to door frame by fitting six (6) tabs
of door frame to six (6) holes of door panel.
5. Hold the door panel to the door frame with four (4)
CHOKE COVER
PUTTY KNIFE
DOOR FRAME
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
REMOVAL
1. Disconnect the oven from the power supply.
2. Push the open button and open the door slightly.
3. Insert an putty knife (thickness of about 0.5mm) into the
2. Push the open button and open the door slightly.
3. Insert an putty knife (thickness of about 0.5mm) into the
gap between the choke cover and door frame as shown
in Figure C-7 to free engaging parts.
in Figure C-7 to free engaging parts.
4. Release choke cover from door panel.
5. Now choke cover is free.
5. Now choke cover is free.
DOOR REPLACEMENT
6. Lift the door upwards.
7. Now, door sub assembly is free from oven cavity.
8. Remove the four (4) screws holding the door panel to
7. Now, door sub assembly is free from oven cavity.
8. Remove the four (4) screws holding the door panel to
the door frame.
Figure C-7. Door Disassembly
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
R-852 - 32
TEST DATA AT A GLANCE
PARTS
SYMBOL
VALUE / DATA
Fuse
F1
20A / 250V
Fuse
F2
F 8A
Thermal cut-out
TC1
125
°
C Off
Thermal cut-out
TC2
150
°
C Off / 130˚C On
Thermistor
Approx. 359.9 k
Ω
- 152 k
Ω
at 20˚C - 30˚C
Top grill heating element
GH1
Approx. 56
Ω
/ Insulation resistance > 10 M
Ω
Bottom grill heating element
GH2
Approx. 106
Ω
/ Insulation resistance > 10 M
Ω
Oven lamp
OL
240–250 V 25W E14
High voltage capacitor
C
AC 2100V 1.16
µ
F
Magnetron
MG
Filament < 1
Ω
/ Filament – chassis
∞
ohm.
High voltage transformer
T
Filament winding < 1
Ω
Secondary winding Approx. 99
Ω
/ Primary winding Approx. 2.4
Ω
WARNING: DISCONNECT THE PLUG WHEN MEASURING RESISTANCE.
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
SHARP
R-852 - 33
Note:
AC CORD CONNECTION
BRN :
AC CORD CONNECTION
BRN :
BROWN
BLU :
BLUE
G-Y :
GREEN AND YELLOW STRIPE
/15 :
SECTIONAL AREA OF 1.5mm
2
MIN.
"
"
Indicates components with potential above 250 V.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. "ENERGY SAVED MODE" APPEARS ON DISPLAY.
1. DOOR CLOSED.
2. "ENERGY SAVED MODE" APPEARS ON DISPLAY.
Figure O-1(c) Oven Schematic-OFF Condition after the oven door is closed.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. " . O" APPEARS ON DISPLAY.
1. DOOR CLOSED.
2. " . O" APPEARS ON DISPLAY.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. PLUGGED IN OVEN.
3. NOTHING APPEARS ON DISPLAY.
1. DOOR CLOSED.
2. PLUGGED IN OVEN.
3. NOTHING APPEARS ON DISPLAY.
Figure O-1(a) Oven Schematic-OFF Condition right after the oven is plugged in.
Figure O-1(b) Oven Schematic-OFF Condition when the oven door is opened.
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
SCHEMATIC
R-852 - 34
Figure O-3(b) Oven Schematic-Grill cooking Condition (BOTTOM GRILL mode)
Figure O-2 Oven Schematic-Microwave cooking Condition
Figure O-3(a) Oven Schematic-Grill cooking Condition (TOP GRILL mode)
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. STRAT KEY TOUCHED.
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. STRAT KEY TOUCHED.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. TOP GRILL MODE SELECTED.
4. STRAT KEY TOUCHED.
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. TOP GRILL MODE SELECTED.
4. STRAT KEY TOUCHED.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. BOTTOM GRILL MODE SELECTED.
4. STRAT KEY TOUCHED.
1. DOOR CLOSED.
2. COOKING TIME ENTERED.
3. BOTTOM GRILL MODE SELECTED.
4. STRAT KEY TOUCHED.
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
OL
CM
TTM
OVEN LAMP
CONVECTION
MOTOR
FAN MOTOR
TURNTABLE MOTOR
GH1: TOP GRILL HEATING ELEMENT
GH2: BOTTOM HEATING ELEMENT
H.V. RECTIFIER
MG:
MAGNETRON
T: HIGH VOLTAGE
TRANSFORMER
T/C TRANSFORMER
C:
CAPACITOR
1.13
µ
F
AC2100V
CONTROL UNIT
A9
A7
RY7
RY5
COM.
COM.
COM.
N.O.
N.O.
COM.
N.O.
N.O.
A3
E1
E3
E5
E7
A1
B2
C3
C1
A5
B1
SW2:
STOP SWITCH
STOP SWITCH
SW1: MONITORED LATCH SWITCH
THERMISTOR
TC1:
MG.
THERMAL
CUT-OUT
MG.
THERMAL
CUT-OUT
TC2:
OVEN
THERMAL
CUT-OUT
OVEN
THERMAL
CUT-OUT
SW3:
MONITOR
SWITCH
MONITOR
SWITCH
4700p/ 250V
4700p/ 250V
10M/ 0.5W
NOISE SUPPRESSION COIL
680 k/ 0.5W
0.22
µ
/250V
F1: FUSE 20A
F2: FUSE F8A
NOISE
FILTER
FILTER
L
N
230V ~ 50Hz
BRN/15
BLU/15
G-Y/15
EARTH
LIVE
NEUTRAL
NC.
NC.
ASYMMETRIC
RECTIFIER
RECTIFIER
RY6
RY1
RY2
RY3
RY4
FM
SCHEMATIC
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