Sharp R820jsf Service Manual

R-820JS
29
PRECAUTIONS FOR USING LEAD-FREE SOLDER
1. Employing lead-free solder
The Control unit PWB of this model employs lead-free solder. This is indicated by the LF symbol printed on the PWB
and in the service manual. The suffix letter indicates the alloy type of the solder.
Example:
Indicates lead-free solder of tin, silver and copper.
2. Using lead-free wire solder
When repairing a PWB with the LF symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder
may result in cold...

R-820JS
30
To remove the outer case, proceed as follows.
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3.Remove the two (2) screws holding the back plate to the
oven cavity rear plate.
4. Remove the back plate with the sub back plate.
5.Remove the two (2) screws from the lower portion of therear cabinet using a T20H Torx type or GTXH20-100
screw driver.
6. Remove the remaining three (3) screws from rear and
along the side edge of case.
7.Slide the entire case back about...

R-820JS
31
POWER TRANSFORMER REMOVAL
6.Disconnect the main wire harness from the power
transformer.
7. Remove the two (2) screws  holding the transformer to
base plate.
8. Remove the transformer.
9. Now the power transformer is free. 1.Disconnect the power supply cord and then remove
outer case.
2. Open the oven door and block it open.
3. Discharge high voltage capacitor.
4.Disconnect the filament leads of power transformer from
high voltage capacitor and the magnetron.
5.Disconnect the H.V. wire B from...

R-820JS
32
COOLING FAN MOTOR REMOVAL POSITIVE LOCK
®  CONNECTOR (NO-CASE TYPE) REMOVAL
Figure C-2.  Positive lock® connector 1.Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Push the lever of positive lock
® connector.
5. Pull down on the positive lock® connector.
CAUTION: WHEN CONNECTING THE POSITIVE LOCK
®
CONNECTORS TO THE TERMINALS, IN-
STALL THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU. 1.Disconnect the power...

R-820JS
33
9.Remove the fan blade from the fan motor shaft according
to the following procedure.
10.Hold the edge of the rotor of the fan motor by using a pair
of groove joint pliers.
CAUTION:
*Make sure that no metal pieces enter the gap
between the rotor and the stator of the fan motor
because the rotor is easily shaven by pliers and
metal pieces may be produced.
*Do not touch the pliers to the coil of the fan motor
because the coil may be cut or injured.
*Do not disfigure the bracket by touching with...

R-820JS
34
DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUST\
MENT
DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVA\
L
oven cavity rear plate.
7. Remove the air duct with the air guide cover and the
partition plate from the oven cavity rear plate.
8. Remove the one  (1) screw holding the thermistor angle
to the oven cavity rear plate. 9.
Remove the thermistor angle together with thermistor
from the oven.
10. Straighten the tab of the thermistor angle holding...

R-820JS
35
REMOVAL
1. Disconnect the power supply cord.
2. Push the open button and open the door slightly.
3. Insert a putty knife (thickness of about 0.5mm) into the
gap between the choke cover and door frame as shown
in Figure C-6 to free engaging parts.
4.Pry the principles of the lever and lift up the choke cover
by inserting a putty knife as shown in Figure C-6.
5. Release choke cover  from door panel.
6. Now choke cover is free.
Figure C-6. Door Disassembly
7.Release two (2) pins of door panel...

R-820JS
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5.Hold the door panel to the door frame with four (4)
screws.
6.Catch two (2) pins of door panel on two (2) hole of upper
and lower oven hinges.
7. Re-install choke cover  to door panel by pushing.
Note: After any service to the door;
(A)Make sure that door sensing switch and secondary
interlock switch are operating properly. (Refer to
chapter Test Procedures.).
(B)An approved microwave survey meter should be
used to assure compliance with proper microwave
radiation emission limitation...

R-820JS
37
6
45
1 2
3
6
45
1 2
3
A
B
C
D
E
F G
H A
B
C
D
E
F G
H
Figure S-1. Pictorial Diagram
REDREDWHT
WHT
WHT
THERMAL 
CUT-OUT
(OVEN) OVEN LAMP 
& SOCKET
THERMAL
CUT-OUT
125 °C(MAG.)
FAN MOTOR
CONVECTION
MOTOR
WHTBLK 
GRYREDBRNWHT
HIGH VOLTAGE COMPONENTS
MAGNETRON
H.V.WIRE A
H.V. 
CAPACITOR
H.V.
RECTIFIER H.V. WIRE B
 POWER
 TRANSFORMER
GRN
WHT
BLK
WHT
BLK
POWER SUPPLY
CORD
WHT
COMWHTWHTRED
WHT
N.C.
N.O.
COM.
GRILL HEATER THERMISTOR
BOTTOM HEATER 
GRY
ORGREDWHT
CN-B
1
1
1
1 18
1
3
2 CN-BCN-D
SP1
T1...

R-820JS
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Figure S-2. Power Unit Circuit
6
45
12
3
6
45
12
3 A
B
C
D
E
F
G
HA
B
C
D
E
F
G
H
A1
C2
C3
C4
C5
COM
CN-A
FAN
MOTOR
B.HEATERCONV.
DOOR 
SENSING
SWITCH.
VRS1
10G471KT1
A155DR
1N4002x4D1 -- D4
C2
470uF/50V D10RY4
CN-C
GND
VC
INT BUZZER
FM
OL
TTM
DOOR SW.
(J1)
C6
C1
0.1uF/50V
R2
510  1/2WR3
510  1/2W
C4
10uF/35VC3
0.1uF/50V
R4
27
D5 D6
Q2
2SB1238
C10
Q3
KRC243MC14B.HEATER
C1VA
C9
VR
LED
NO
COM
D9 RY3
NO
COM
D8 RY2
A3
D12RY5
A5
D7RY1
NO
COM
D11 RY6
B1B2D1D3
C8
C7
C17
C16
C12
C15
OVEN TH.
OL TTM...