Sharp R-234 (serv.man4) Service Manual ▷ View online
R-234 - 17
TEST PROCEDURES
Remove the outer case and check voltage between Pin No 5 of the 3 pin connector (A) and common
terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
RY1 and RY2 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 diode is good,
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 / Turntable motor / Cooling fan motor
RY2
Approx. 7.0V D.C.
Power transformer
M
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED
WIRING BOARD (PWB) IS OPEN
NOTE: *At the time of making these repairs,
make a visual inspection of the varistor.
Check for burned damage. If any ab-
normal condition is detected, replace
the defective parts.
Check for burned damage. If any ab-
normal condition is detected, replace
the defective parts.
To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit
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.
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.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
The rated voltage is not applied between Pin
Check supply voltage and oven power cord.
No. 5 of the 3 pin connector (A) and the
common terminal of the relay RY2.
2
Only pattern at "a" is broken.
*Insert jumper wire J1 and solder.
3
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
L
RELAY TEST
K
TACT SWITCH TEST
1. Disconnect the oven from the power supply.
2. Discharge the high voltage capacitor.
3. Remove the control unit from the control panel.
4. By using an ohmmeter, check the tact switch operation.
5. When the tact switch is not depressed, an ohmmeter should indicate an open circuit. When the tact
2. Discharge the high voltage capacitor.
3. Remove the control unit from the control panel.
4. By using an ohmmeter, check the tact switch operation.
5. When the tact switch is not depressed, an ohmmeter should indicate an open circuit. When the tact
switch is depressed, an ohmmeter should indicate a short circuit. If improper operation is indicated,
the tact switch is probably defective and should be checked.
the tact switch is probably defective and should be checked.
RY2
R70
D70
1
5
(J1)
a
c
d
b
RY1
D71
D1
ZD70
VRS1
R1
CN - A
PROCEDURE
LETTER
COMPONENT TEST
R-234 - 18
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
4) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
light the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (tact switch touch sound and completion
sound).
audible sounds (tact switch touch sound and completion
sound).
6) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
7) Stop Switch
A switch to "tell" the LSI if the door is open or closed.
8) 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.
9) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED3)
LED1-LED3)
The touch control section consists of the following circuits as
shown in the touch control panel circuit.
shown in the touch control panel circuit.
The principal functions of these circuits and their related
signals are explained below.
signals are explained below.
Tact Switch
Signals generated in the LSI are sent to the tact switches
through R60, R61,R62 and R63.
When a tact switch is touched, a signal is completed through
the tact switch and passed back to the LSI through R81 to
perform the function that was requested.
Signals generated in the LSI are sent to the tact switches
through R60, R61,R62 and R63.
When a tact switch is touched, a signal is completed through
the tact switch and passed back to the LSI through R81 to
perform the function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchroniz-
ing signal circuit and back light circuit.
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchroniz-
ing signal circuit and back light circuit.
1) ACL
This circuit generates a signal which resets the LSI to the
initial state when power is supplied.
initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.
common electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltage necessary in the control unit
from the AC line voltage. In addition, the synchronizing
signal is available in order to compose a basic standard
time in the clock circuit.
from the AC line voltage. In addition, the synchronizing
signal is available in order to compose a basic standard
time in the clock circuit.
Symbol
Voltage
Application
VC
+5V
LSI(IC1)
R-234 - 19
1-12
SEG0 -
OUT
Segment data signal.
SEG11
Connected to LCD.
The relation between signals are as follows:
The relation between signals are as follows:
LSI signal (Pin No.)
LCD segment
LSI signal (Pin No.) LCD segment
SEG 0 (1) ................................ S6
SEG 6 (7) ........................... S12
SEG 1 (2) ................................ S7
SEG 7 (8) ............................. S5
SEG 2 (3) ................................ S8
SEG 8 (9) ............................. S4
SEG 3 (4) ................................ S9
SEG 9 (10) ........................... S3
SEG 4 (5) .............................. S10
SEG 10 (11) ......................... S2
SEG 5 (6) .............................. S11
SEG 11 (12) ......................... S1
13
R60
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW4 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW4 is touched.
14
R61
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW3 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW3 is touched.
15
R62
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW2 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW2 is touched.
16
R63
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW1 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW1 is touched.
17
AIN0
IN
To input signal which communicates the door open/close information to LSI.
Door close "L" level signal (0V). Door open "H" level (+5V)
Door close "L" level signal (0V). Door open "H" level (+5V)
18-20
AIN1-AIN3
IN
Terminal to change functions according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its function.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its function.
21
VSS
IN
Power source voltage: 0V.
VSS voltage of power source circuit input.
VSS voltage of power source circuit input.
22
R70
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay
(RY2). The signals holds "L" level
during microwave cooking and "H"
level while not cooking. In other cook-
ing modes (variable cooking) the sig-
nal turns to "H" level and "L" level in
repetition according to the power level.
(RY2). The signals holds "L" level
during microwave cooking and "H"
level while not cooking. In other cook-
ing modes (variable cooking) the sig-
nal turns to "H" level and "L" level in
repetition according to the power level.
23
R71
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
24
R72
OUT
Oven 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.
square waveform voltage is delivered to
the RY1 driving circuit.
25
R73
IN
Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into R73.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into R73.
26
INT2
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
DESCRIPTION OF LSI
LSI(IXA084DR)
The I/O signal
The I/O signal
of the LS
I(IXA084DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
HIGH
H : +5V
L : 0V
H : +5V
L : 0V
MEDIUM
HIGH
ON
ON
OFF
OFF
OFF
24 sec.
8 sec.
A
B
0.1 sec.
2 sec.
H : +5V
L: 0V
H : +5V
L: 0V
20.0 msec
During cooking
H : +5V
L : 0V
20.0 msec
H : +5V
L : 0V
R-234 - 20
Pin No.
Signal
I/O
Description
27
R81
IN
Signal coming from tact switch.
When either of tact switches SW1-SW4 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R81. When no key is touched, the signal
is held at "H" level.
When either of tact switches SW1-SW4 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R81. When no key is touched, the signal
is held at "H" level.
28
INT1
IN
Signal coming from encoder.
Signal similar to R73. Pulse signals are input into INT1.
Signal similar to R73. Pulse signals are input into INT1.
29
R83
OUT
Terminal not used.
30-32
R90-R92
OUT
Terminal not used.
33
XIN
IN
Internal clock oscillation frequency setting input.
The internal clock frequency is set by inserting the capacitor and resistor circuit with
respect to XOUT terminal.
The internal clock frequency is set by inserting the capacitor and resistor circuit with
respect to XOUT terminal.
34
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Output to control oscillation input of XIN.
35
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set "L" level the moment power is supplied, at this time the LSI is reset.
Thereafter set at "H" level.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set "L" level the moment power is supplied, at this time the LSI is reset.
Thereafter set at "H" level.
36
HOLD
IN/OUT
Connected to VDD.
37
VLC
IN
Signal synchronized with commercial power source frequency.
Signal similar to VSS.
Signal similar to VSS.
38
COM1
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 1)
Connected to LCD (Pin No. 1)
39
COM2
OUT
Common data signal: COM2.
Connected to LCD (Pin No. 2)
Connected to LCD (Pin No. 2)
40
COM3
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 3)
Connected to LCD (Pin No. 3)
41
COM4
OUT
Terminal not used.
42
VDD
IN
Power source voltage input terminal.
Connected to VC.
DESCRIPTION OF LSI
LSI(IXA084DR)
The I/O signal
The I/O signal
of the LS
I(IXA084DR) are detailed in the following table.
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