Sharp R-23AM (serv.man3) Service Manual ▷ View online
15
R - 2 2 A T
R-23AM
R - 2 4 A T
R-23AM
R - 2 4 A T
Switches Terminals
Released
Depressed
SW1
F1 - F4
O.C.
S.C.
SW2
F1 - F5
O.C.
S.C.
SW3
F2 - F4
O.C.
S.C.
SW4
F2 - F5
O.C.
S.C.
SW5
F3 - F4
O.C.
S.C.
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 3D CHECKS.
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable 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.
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable 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.
CARRY OUT 4R CHECKS.
SWITCH UNIT TEST FOR R-23AM
1. CARRY OUT 3D CHECKS.
2. Remove the switch unit from the control panel, referring to control panel removal.
3. To test the switches (SW1-SW5) on the switch unit, check between the terminals of the connector
2. Remove the switch unit from the control panel, referring to control panel removal.
3. To test the switches (SW1-SW5) on the switch unit, check between the terminals of the connector
CN-F as described in the following table by using ohmmeter when the switches are released and
depressed.
depressed.
4. If incorrect readings are obtained, replace the
defective switch.
5. CARRY OUT 4R CHECKS.
P
KEY UNIT TEST FOR R-24AT / R-22AT
a) When rotating the encoder, the cooking time can not be entered.
3. Control Unit
The following symptoms may indicate a defective control unit. Replacing the control unit. Before
replacing the control unit, perform the switch unit test (Procedure P) to determine if control unit is faulty.
replacing the control unit, perform the switch unit test (Procedure P) to determine if control unit is faulty.
3-1 Programming problems.
a) When touching the buttons, a certain group of buttons do not produce a signal.
3-2 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.
3-3 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.C. : Open Circuit / S.C. : Short Circuit
SET
3
4
5
6
7
8
9
0
2
CHECK
VOLUME
START
STOP /
CLEAR
CLEAR
1
11
12
13
14
15
16
19
20
17
18
DOUBLE
QUANTITY
EXPRESS
DEFROST
DEFROST
MANUAL /
REPEAT
POWER
LEVEL
G12
G11
G10
G 9
G 8
G 7
G 6
G 5
G 4
G 3
G 2
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.
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 For R-24AT / R-22AT
These relays are operated by D.C. voltage.
These relays are operated by D.C. voltage.
Q
RELAY TEST
16
R - 2 2 A T
R-23AM
R - 2 4 A T
R-23AM
R - 2 4 A T
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.
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
OCCURRENCE
CAUSE OR CORRECTION
1
The rated AC voltage is not present at
Check supply voltage and oven power cord.
POWER terminal of CPU connector (CN-A).
2
The rated AC voltage is present at primary
Low voltage transformer or secondary circuit defective.
side of low voltage transformer.
Check and repair.
3
Only pattern at "a" is broken.
*Insert jumper wire J24 and solder for R-24AT / R-22AT.
*Insert jumper wire J9 and solder for R-23AM.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
*Insert jumper wire J9 and solder for R-23AM.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR)
(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.
resistance). If any abnormal condition is detected, replace the defective parts.
CARRY OUT 4R CHECKS.
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
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 motors
RY3
APPROX. 16.0V D.C.
High voltage transformer 1
RY4
APPROX. 18.0V D.C.
High voltage transformer 2
RY1, RY2 and RY3 Relay Test For R-23AM
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 diode
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. 18.0V D.C.
Oven lamp, Blower motor and Stirrer motors
RY2
APPROX. 17.5V D.C.
High voltage transformer 1
RY3
APPROX. 17.5V D.C.
High voltage transformer 2
CARRY OUT 4R CHECKS.
R
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN
BOARD(PWB) IS OPEN
(J29)
(VRS2)
VRS1
(J24)
(J23)
(9)
9(7)
5(3)
3(1)
RY1
D81
c
a
b
d
S1
S2
2
3
P
TI
C31
D23
+
–
VRS1
(J9)
(J8)
OL, BM
POWER
7
5
3
1
D21
CN–A
a
c
b
d
R-24AT / R-22AT
R-23AM
17
R - 2 2 A T
R-23AM
R - 2 4 A T
R-23AM
R - 2 4 A T
This AC voltage is the input to the IN3 and IN5 ports of
IC1, which determines if there is a magnetron / high
voltage problem.
IC1, which determines if there is a magnetron / high
voltage problem.
Figure T-1. High Voltage Monitoring Circuit For R-24AT / R22AT
14) Magnetron Temperature Circuit.
(Detect Noload or Fan Lock)
This is a circuit for transmitting output change of thermis-
tor (Magnetron thermistor) to IC1.
tor (Magnetron thermistor) to IC1.
15) Oven Cavity Temperature Detecting Circuit.
This is a circuit for transmitting output change of thermis-
tor (Oven thermistor (2)) to IC1.
tor (Oven thermistor (2)) 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 10 are set as follows: fig.1.
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 10 are set as follows: fig.1.
Memory No.
Cook Time
Output Power
1
5 sec.
100%
2
10 sec.
100%
3
20 sec.
100%
4
30 sec.
100%
5
40 sec.
100%
6
50 sec.
100%
7
1 min.
100%
8
1 min.15 sec.
100%
9
1 min.30 sec.
100%
10
2 mins.
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
50%
30%
20%
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.
TOUCH CONTROL PANEL ASSEMBLY FOR R-24AT / R-22AT
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 voltages required
at each part by full wave rectifying circuit, constant
voltage circuit, etc..
of the low voltage (T1) transformer to voltages 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 Synchronizing Signal Generating Circuit
This is a circuit for generating power synchronizing 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.
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.
4) Clock Circuit
This is a circuit for controlling clock frequency required for
operating IC1.
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 (Oven thermistor (1)) to IC1.
tor (Oven thermistor (1)) 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/
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.
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/
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.
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
18
R - 2 2 A T
R-23AM
R - 2 4 A T
R-23AM
R - 2 4 A T
CONTROL PANEL ASSEMBLY FOR R-23AM
OUTLINE OF CONTROL PANEL
The control section consists of the following units as
shown in the control panel circuit.
shown in the control panel circuit.
(1) Control Unit
(2) Switch Unit
(3) Encoder Unit
(2) Switch Unit
(3) Encoder 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 switch touch and oven function control are all
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..
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.
3) Power Synchronizing Signal Generating Circuit
This is a circuit for generating power synchronizing
signal by virtue of the secondary side output of trans-
former T1.
former T1.
This signal is used for a basic frequency to time
processing and so on.
4) Clock Circuit
This is a circuit for controlling clock frequency required
for operating IC1.
5) IC1 (Main Processor)
This is a one-chip microcomputer, responsible for
controlling the entire control unit.
6) Display Circuit
This is a circuit for driving display tubes by IC1 output.
7) Switch Input Circuit
This is a circuit for transmitting switch input information
to IC1.
8) Sound-body Driving Circuit
This is a circuit for driving sound body by IC1 output.
9) Relay Driving Circuit
This is a circuit for driving output relay by IC1 output.
10) Stop Switch Circuit
This is a circuit for driving IC1 to detect door opening/
closing.
11) Exhaust Air Temperature Detecting Circuit
This is a circuit for transmitting output change of
thermistor (Oven thermistor (1)) to IC1.
thermistor (Oven thermistor (1)) to IC1.
12) 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 pri-
mary winding of the current transformers CT1 and
CT2. This causes a current to be induced in the
secondary windings of CT1/CT2 and results in an AC
voltage which is determined by R30/R31. This AC
voltage is then half wave rectified by D30/D31 and
smoothed (filtered) by C30/C31. This AC voltage is the
input to the AN3 and AN4 ports of IC1, which deter-
mines if there is a magnetron / high voltage problem.
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 pri-
mary winding of the current transformers CT1 and
CT2. This causes a current to be induced in the
secondary windings of CT1/CT2 and results in an AC
voltage which is determined by R30/R31. This AC
voltage is then half wave rectified by D30/D31 and
smoothed (filtered) by C30/C31. This AC voltage is the
input to the AN3 and AN4 ports of IC1, which deter-
mines if there is a magnetron / high voltage problem.
Figure T-1. High Voltage Monitoring Circuit For R-23AM
13) Magnetron Temperature Detecting Circuit.
This is a circuit for transmitting output change of
thermistor (Magnetron thermistor) to IC1.
thermistor (Magnetron thermistor) to IC1.
14) Oven Cavity Temperature Detecting Circuit.
This is a circuit for transmitting output change of
thermistor (Oven thermistor (2)) to IC1.
thermistor (Oven thermistor (2)) to IC1.
2. Switch Unit
The switch unit is composed of a matrix circuit in which
when a switch it touched, one of signals P43 - P45
generated by the LSI, is passed through the switch and
returned to the LSI as one of signals P50 - P51.
when a switch it touched, one of signals P43 - P45
generated by the LSI, is passed through the switch and
returned to the LSI as one of signals P50 - P51.
3. Encoder
The encoder converts the signal generated by LSI into
the pulse signal, and the pulse signal is returned to the
LSI.
the pulse signal, and the pulse signal is returned to the
LSI.
HIGH VOLTAGE TRANSFORMER
HIGH VOLTAGE CIRCUIT
MAIN BODY SIDE
MAIN BODY SIDE
T/C SIDE
CT1 or CT2
RY2 or RY3
R30 or
R31
R31
R34 or
R35
R35
D30 or
D31
D31
R32 or
R33
R33
Vc
C30 or C31
IC1
AN3 or
AN4 PORT
AN3 or
AN4 PORT
D32 or
D33
D33
DESCRIPTION OF LSI FOR R-24AT / R-22AT
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
1
VREF
IN
Reference voltage input terminal.
A reference voltage applied to the A/D converter in the LSI. Connected to GND.(0V)
Click on the first or last page to see other R-23AM (serv.man3) service manuals if exist.