Sharp R308jsf Service Manual

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41 P70 OUTOven lamp, fan motor and turntable motor driving signal
To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to the
RY1 driving circuit and RY2 control circuit.
42 P71 OUT Terminal not used.
43 P72 OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).  The
signals holds “L” level during microwave cook-
ing and “H” level while not cooking. In other
cooking modes (variable cooking) the signal...

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20 1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the circuits.
When handling these parts, the following precautions should
be strictly followed. CMOS LSI have extremely high impedance
at its input and output terminals. For this reason, it is easily
influenced by the surrounding high voltage power source,
static electricity charge in clothes, etc. and sometimes it is not
fully protected by the built-in protection circuit....

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PRECAUTIONS FOR USING LEAD-FREE SOLDER
1. Employing lead-free solder
The Main 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...

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22 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 wire leads (primary) from power transformer
and the filament leads and high voltage wire from the
magnetron and capacitor terminals.
5.Remove four (4) screws (two (2) screws from the upper side
and two (2) screws from bottom side) holding transformer to
bottom plate.
6. Remove transformer from bottom plate.
HIGH...

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23 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, CON-
NECT THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU
Figure C-1.  Positive lock
® connector
POSITIVE LOCK®  CONNECTOR (NO-CASE TYPE) REMOVALMAGNETRON REMOVAL...

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24 switch to the small depression on the surface of the control
panel frame.
5. Attach the membrane switch to the control panel frame by
rubbing with a soft cloth not to scratch.
6. Tear the backing paper from the new graphic sheet.
7. Adjust the upper edge and left edge of the graphic sheet to
the large depression on the surface of the control panel
frame.
8.Attach the graphic sheet to the control panel frame by
rubbing with a soft cloth not to scratch.
9. Make sure that...

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25 Side View Rear View INSTALLATION
1. Install the fan blade to the fan motor shaft according to the
following procedure.
2. Hold the center of the bracket which supports the shaft of
the fan motor on the flat table.
3.Apply the screw lock tight into the hole (for shaft) of the fan
blade.
4.Install the fan blade to the shaft of fan motor by pushing the
fan blade with a small, light weight, ball peen hammer or
rubber mallet.5. Install the fan motor to the oven cavity back...

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26 4.
Reinstall outer case and check for microwave leakage
around door with an approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
2.
The door sensing switch and secondary interlock switch
interrupt the circuit before the door can be open.
3. Monitor switch contacts close when door is opened.
REMOVAL
1. Disconnect the power supply cord.
2. Open the door slightly.
3. Insert a putty knife (thickness of about 0.5mm) into the gap between the choke...

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6
45
12
3
6
45
12
3 A
B
C
D
E
F
G
HA
B
C
D
E
F
G
H
Figure S-1. Pictorial Diagram
HIGH VOLTAGE
CAPACITOR
H.V. RECTIFIERPOWER SUPPLY 
CORD 120V 60Hz
HIGH VOLTAGE COMPONENTS
MAGNETRON
COM.MONITOR
SWITCH
COM.N.O.
N.C.
DOOR
SENSING
SWITCH
SECONDARY
INTERLOCK
SWITCH
TURNTABLE
MOTOR
POWER 
TRANSFORMER
COM.NO
NOTE:
The neutral (WHT) wire must be 
connected to the terminal with N 
mark on the power supply cord.
GRY
W
H
T
WHT
GRYRED
GRYGRY
R
E
DP
N
K B
L
K
R
E
D
GRN
GRYGRY
GRN...

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Figure S-2. Control 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
SEG14
AIN1
AIN0
SEG0
P20VLC2
VLC1
VLC0
CAPL
CAPH
P70
AI N 5
P03
COM0
IC-1
AI N 2 AI N 3 AI N 4 SEG13 SEG12 SEG11 SEG10SEG9 SEG8 SEG7
P11
P10
P33
P32
P31
INTP0
P26
P25 AVSS
P24
P23
P22
BZO90
1 4832
49
6416
33
B2COMNONO
RY1
RY2
D20 D21
Q21
DTD143ES
C21
10uF/35V+
-
D22
D40Q22 SP1
C1
1000uF/25V+
-
C12
0.1uF/50V
0.1uF/25V
+
-C8
220uF/10V
ZD1
HZ4B3
C10
0.1uF/25V
R5
Q1
R6
15KC4
0.01uF/25V
Q10...