Sharp R-2297G (serv.man2) Service Manual ▷ View online
15
R-2297G
R-2397G
R-2397G
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
L (min)
Cx
±
20%
Cy
±
20%
0.5mH
0.22
µ
F
4700 pF
MEASURING POINT
INDICATION OF OHMMETER
Between N and L
Open circuit
Between terminal N and WHITW
Short circuit
Between terminal L and BLK
Short circuit
If incorrect readings are absorbed, replace the noise filter.
CARRY OUT 4R CHECKS.
L
N
L
L
F1
Cy
BLK
WHT
Cx
N
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, IC, etc.
Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with
only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided
into two units, Control Unit and Key Unit, troubleshooting by unit replacement is described according
to the symptoms indicated.
1. Key Unit
Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with
only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided
into two units, Control Unit and Key Unit, troubleshooting by unit replacement is described according
to the symptoms indicated.
1. Key Unit
The following symptoms indicate a defective key unit. Replace the key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching the pads, sometimes a pad produces no signal.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching the pads, sometimes a pad produces no signal.
2. Control Unit
The following symptoms may indicate a defective control unit. Replacing the control unit.
2-1 Programming problems.
a) When touching the pads, a certain group of pads do not produce a signal.
2-2 Display problems.
a) For a certain digit, all or some segments do not light up.
b) For a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
b) For a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Cooking is not possible.
b) Cooking is not possible.
O
KEY UNIT TEST
SET
3
4
5
6
7
8
9
0
G 1
G 2
G 3
G 4
G 5
G 6
G 7
G 8
G 9
G 10
G 11
G 12
2
CHECK
VOLUME
START
STOP /
CLEAR
CLEAR
1
DOUBLE
QUANTITY
EXPRESS
DEFROST
DEFROST
MANUAL /
REPEAT
POWER
LEVEL
If the display fails to clear when the STOP/CLEAR pad is depressed, fir st verify the flat ribbon is
making good contact, verify that the door sensing switch (stop switch ) operates properly; that is the
contacts are closed when the door is closed and open when the door is open. If the door sensing
switch (stop switch ) is good, disconnect the flat ribbon cable that connects the key unit to the control
unit and make sure the door sensing switch is closed (either close the door or short the stop switch
connector ). Use the key unit matrix indicated on the control panel schematic and place a jumper
wire between the pins that correspond to the STOP/CLEAR pad making momentary contact. If the
control unit responds by clearing with a beep, the key unit is faulty and must be replaced. If the control
unit does not respond, it is faulty and must be replaced. If a specific pad does not respond, the above
method may be used (after
clearing the control unit ) to
determine if the control unit or
key pad is at fault.
making good contact, verify that the door sensing switch (stop switch ) operates properly; that is the
contacts are closed when the door is closed and open when the door is open. If the door sensing
switch (stop switch ) is good, disconnect the flat ribbon cable that connects the key unit to the control
unit and make sure the door sensing switch is closed (either close the door or short the stop switch
connector ). Use the key unit matrix indicated on the control panel schematic and place a jumper
wire between the pins that correspond to the STOP/CLEAR pad making momentary contact. If the
control unit responds by clearing with a beep, the key unit is faulty and must be replaced. If the control
unit does not respond, it is faulty and must be replaced. If a specific pad does not respond, the above
method may be used (after
clearing the control unit ) to
determine if the control unit or
key pad is at fault.
16
R-2297G
R-2397G
R-2397G
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 5 and 7 of the connector (A) on the
control unit with an A.C. voltmeter. The meter should indicate 230~240 volts, if not check control unit
circuity.
control unit with an A.C. voltmeter. The meter should indicate 230~240 volts, if not check control unit
circuity.
RY1, RY3 and RY4 Relay Test
These relays are operated by D.C. voltage.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
These relays are operated by D.C. voltage.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated .............................Defective relay.
DC. voltage not indicated ....................... Check diode which is connected to the relay coil. If
DC. voltage not indicated ....................... Check diode which is connected to the relay coil. If
diode is good, control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
APPROX. 19.0V D.C.
Oven lamp, Blower motor and Stirrer motor
RY3
APPROX. 16.0V D.C.
Power transformer 1
RY4
APPROX. 18.0V D.C.
Power transformer 2
CARRY OUT 4R CHECKS.
P
RELAY TEST
Q
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN
BOARD(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary
on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide
given below for repair.
on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide
given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
OCCURANCE
CAUSE OR CORRECTION
1
2
3
4
Pattern at "a" and "b" are broken.
The rated AC voltage is not present at
POWER terminal of CPU connector (CN-A)
POWER terminal of CPU connector (CN-A)
The rated AC voltage is present at primary
side of low voltage transformer.
side of low voltage transformer.
Only pattern at "a" is broken.
Low voltage transformer or secondary circuit
deffective. Check and repair.
deffective. Check and repair.
*Insert jumper wire J24 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
(CARRY OUT 3D CHECKS BEFORE REPAIR)
Check supply voltage and oven power cord.
*Insert the coil RCILF2003YAZZ between "c" and
"d". (CARRY OUT 3D CHECKS BEFORE
REPAIR)
"d". (CARRY OUT 3D CHECKS BEFORE
REPAIR)
NOTE: *At the time of these repairs, make a
visual inspection of the varistor for
burning damage and examine the
transformer with tester for the presence
of layer short-circuit (check primary
coil resistance). If any abnormal
condition is detected, replace the
defective parts.
burning damage and examine the
transformer with tester for the presence
of layer short-circuit (check primary
coil resistance). If any abnormal
condition is detected, replace the
defective parts.
CARRY OUT 4R CHECKS.
(J29)
(VRS2)
VRS1
(J24)
(J23)
(9)
9(7)
5(3)
3(1)
RY1
D81
c
a
b
d
17
R-2297G
R-2397G
R-2397G
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the touch control panel circuit.
shown in the touch control panel circuit.
(1) Control Unit
(2) Key Unit
(2) Key Unit
The principal functions of these units and the signals commu-
nicated among them are explained below.
nicated among them are explained below.
1. Control Unit
Signal of key touch and oven function control are all
processed by one microcomputer.
processed by one microcomputer.
1) Power Supply Circuit
This circuit changes output voltage at the secondary side
of the low voltage (T1) transformer to volatges required
at each part by full wave rectifying circuit, constant
voltage circuit, etc..
of the low voltage (T1) transformer to volatges required
at each part by full wave rectifying circuit, constant
voltage circuit, etc..
2) ACL Circuit
This is an Auto-clear Circuit, i.e., a reset circuit, which
enables IC1 to be activated from initial state.
enables IC1 to be activated from initial state.
3) Power SYNC Signal Generating Circuit
This is a circuit for generating power SYNC signal by
virtue of the secondary side output of transformer T1.
This signal is used for a basic frequency to time process-
ing and so on.
virtue of the secondary side output of transformer T1.
This signal is used for a basic frequency to time process-
ing and so on.
4) Clock Circuit
This is a circuit for controlling clock frequency required
for operating IC1.
for operating IC1.
5) IC1 (Main Processor)
This is a one-chip microcomputer, responsible for con-
trolling the entire control unit.
trolling the entire control unit.
6) IC2 (Memory Processor)
This is a memory IC, responsible for memory function.
7) Display Circuit
This is a circuit for driving display tubes by IC1 output.
8) Key Input Circuit
This is a circuit for transmitting key input information to
IC1.
IC1.
9) Sound-body Driving Circuit
This is a circuit for driving sound body by IC1 output.
10) Relay Driving Circuit
This is a circuit for driving output relay by IC1 output.
11) Stop Switch Circuit
This is a circuit for driving IC1 to detect door opening/
closing.
closing.
12) Exhaust Air Temperature Detecting Circuit
This is a circuit for transmitting output change of thermis-
tor (Exhaust Air Temperature Sensor) to IC1.
tor (Exhaust Air Temperature Sensor) to IC1.
13) High Voltage Monitoring Circuit.
This circuit detects problems in the magnetron / high
voltage circuit by sensing a variation in the current
flowing through the primary winding of the high voltage
transformer.
During heating, the primary current of the high voltage
transformers also flows through the primary winding of
the current transformers CT1 and CT2. This causes a
current to be induced in the secondary windings of CT1/
voltage circuit by sensing a variation in the current
flowing through the primary winding of the high voltage
transformer.
During heating, the primary current of the high voltage
transformers also flows through the primary winding of
the current transformers CT1 and CT2. This causes a
current to be induced in the secondary windings of CT1/
HIGH VOLTAGE TRANSFORMER
HIGH VOLTAGE CIRCUIT
MAIN BODY SIDE
MAIN BODY SIDE
T/C SIDE
CT1 or CT2
RY3 or RY4
R61 or
R62
R62
R65 or
R66
R66
D61 or
D62
D62
R63 or
R64
R64
Vc
C61 or C62
IC1
IN3 or
IN5 PORT
IN3 or
IN5 PORT
D63 or
D64
D64
CT2 and results in an AC voltage which is determined
by R61/R62.
This AC voltage is then half wave rectified by D61/D62
and smoothed (filtered) by C61/C62.
This AC voltage is the input to the IN3 and IN5 ports of
IC1, which determines if there is a magnetron / high
voltage problem.
by R61/R62.
This AC voltage is then half wave rectified by D61/D62
and smoothed (filtered) by C61/C62.
This AC voltage is the input to the IN3 and IN5 ports of
IC1, which determines if there is a magnetron / high
voltage problem.
Figure T-1. High Voltage Monitoring Circuit
14) Magnetron Temperature Circuit.
(Detect Noload or Fan Lock)
This is a circuit for transmitting output change of thermis-
tor (Magnetron Sensor) to IC1.
tor (Magnetron Sensor) to IC1.
15) Intake Air Temperature Detecting Circuit.
This is a circuit for transmitting output change of thermis-
tor (Intake Air Sensor) to IC1.
tor (Intake Air Sensor) to IC1.
2. Key Unit
The key unit is composed of a matrix circuit in which
when a key it touched, one of signals P11, P12, P15, P16
and P17 generated by the LSI, is passed through the key
and returned to the LSI as one of signals R0--R3. This
model has 20 Memory pads. When the oven is shipped,
Memory pad 1 to 5 are set as follows: fig.1.
when a key it touched, one of signals P11, P12, P15, P16
and P17 generated by the LSI, is passed through the key
and returned to the LSI as one of signals R0--R3. This
model has 20 Memory pads. When the oven is shipped,
Memory pad 1 to 5 are set as follows: fig.1.
Memory No.
Cook Time
Output Power
1
10 sec.
100%
2
20 sec.
100%
3
30 sec.
100%
4
45 sec.
100%
5
1 min.
100%
(fig. 1)
This model has a double quantity pad. When the oven
is shipped, Magnification "1.8" is preset in the double
quantity pad. This model has an defrost pad. When
the oven is shipped, defrost is set as follows: fig.2.
is shipped, Magnification "1.8" is preset in the double
quantity pad. This model has an defrost pad. When
the oven is shipped, defrost is set as follows: fig.2.
1STAGE
2STAGE
3STAGE
POWER
40%
30%
10%
DEFROSTING TIME 0.2T+20sec. 0.13T+30sec. 0.67T-50sec.
(fig. 2)
NOTE :
"CHECK" indicator will flash at half of defrosting time.
"CHECK" indicator will flash at half of defrosting time.
18
R-2297G
R-2397G
R-2397G
1
VREF
IN
Reference voltage input terminal.
A reference voltage applied to the A/D converter in the LSI. Connected to
A reference voltage applied to the A/D converter in the LSI. Connected to
GND.(0V)
2
IN7
IN
Temperature measurement input: MAGNETRON THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the
By inputting DC voltage corresponding to the temperature detected by the
thermistor, this input is converted into temperature by the A/D converter built into
the LSI.
the LSI.
3
IN6
IN
Temperature measurement input: EXHAUST THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the
By inputting DC voltage corresponding to the temperature detected by the
thermistor, this input is converted into temperature by the A/D converter built into
the LSI.
the LSI.
4
IN5
IN
A/D input for troubleshooting Magnetron 1.
5
IN4
IN
Terminal to change functions according to the model.
Signal in accordance with the model in operation is applied to set up its function.
Signal in accordance with the model in operation is applied to set up its function.
6
IN3
IN
A/D input for troubleshooting Magnetron 2.
7
IN2
IN
Connected to GND.(0V)
8
IN1
IN
Terminal not used.
9
IN0
IN
Temperature measurement input: INTAKE THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the
By inputting DC voltage corresponding to the temperature detected by the
thermistor, this input is converted into temperature by the A/D converter built into
the LSI.
the LSI.
10
P47
OUT
Terminal not used.
11
P46
OUT
Memory (EEPROM) clock output.
12
P45
IN/OUT
Memory (EEPROM) data input/output.
13-14
P44-P43
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay. In 100% power level operation, "L" level during
To turn on and off the cook relay. In 100% power level operation, "L" level during
cooking; "H" level otherwise. In other power level operation (90,80,70,60,50,40,30,20,10
or 0%), "H" and "L" level is repeated according to power level.
or 0%), "H" and "L" level is repeated according to power level.
Power level
ON
OFF
Power level
ON
OFF
100%
48sec. 0sec.
40%
22sec.
26sec.
90%
44sec. 4sec.
30%
16sec.
32sec.
80%
40sec. 8sec.
20%
12sec.
36sec.
70%
36sec. 12sec.
10%
8sec.
40sec.
60%
32sec. 16sec.
0%
0sec.
48sec.
50%
26sec. 22sec.
15
P42
OUT
Power supply output at thermistor detecting circuit.
(Output -5V in cooking only, but apply high impedance to others to prevent
(Output -5V in cooking only, but apply high impedance to others to prevent
thermistor from electrolytic corrosion ocurrence.)
16
P41
OUT
Terminal not used.
17
P40
OUT
Oven lamp, Blower motor and Stirrer motor driving signal. (Square Wave-
form : 50Hz)
To turn on and off the shut-off relay (RY1).
The Square waveform voltage is delivered to
the RY1 relay driving circuit and
relays(RY3,RY4,COOK RELAY) control cir-
cuit.
the RY1 relay driving circuit and
relays(RY3,RY4,COOK RELAY) control cir-
cuit.
18-22
P37-P33
OUT
Terminal not used.
23
P32
OUT
Signal to sound buzzer.
This signal is to control the 2.5kHz
This signal is to control the 2.5kHz
continuous signal.
A: key touch sound.
B: Guydance sound.
C: Completion sound.
B: Guydance sound.
C: Completion sound.
DESCRIPTION OF LSI
LSI(IZA646DR)
The I/O signal of the LSI(IZA646DR) is detailed in the following table.
The I/O signal of the LSI(IZA646DR) is detailed in the following table.
Pin No.
Signal
I/O
Description
GND
-5V
48 sec.
OFF
ON
H
L
20 msec
During cooking
A
B
C
0.12 sec
2.4 sec
1.2 sec
1.2 sec
GND
-5V
T
200µsec.
200µsec.
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