Sharp R-32STM Service Manual ▷ View online
R32STM - 9
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
D
RELAY TEST
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.
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 J1 and solder.
(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)
NOTE: *At the time of these repairs, make a visual inspection of the varistor for burning damage
E
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN.
(PWB) IS OPEN.
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.
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.
CN - E
CN - D
D25
a
b
c
d
VRS1
CN - A
RY6
(J1)
1
3
5
31
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 4 pin connector (E) on the
control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
Relay Test
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
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. 24.0V D.C.
Oven lamp / Turntable motor / Fan motor
RY2
Approx. 18.0V D.C.
High voltage transformer
CARRY OUT 4R CHECKS.
R32STM - 10
TOUCH CONTROL PANEL ASSEMBLY
3) 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.
4) ACL
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
the initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion
sound).
audible sounds (key touch sound and completion
sound).
6) Door Sensing Switch (Stop Switch)
A switch to "tell" the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
light the oven lamp.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1 - LD5).
LD1 - LD5).
9) Indicator Circuit
This circuit consists of 7-digits, 30-segments and 4-
common electrodes using a Liquid Crystal Display.
common electrodes using a Liquid Crystal Display.
(1) Key Unit
(2) Control Unit
(2) Control Unit
The principal functions of these units and signals com-
municated among them are explained below.
municated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated
in the LSI are sent to the key unit from P11 - P17.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI through
P20 - P23 to perform the function that was requested.
in the LSI are sent to the key unit from P11 - P17.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI through
P20 - P23 to perform the function that was requested.
Control Unit
Control unit consists of LSI, power source circuit,
synchronizing signal circuit, ACL circuit, buzzer circuit,
indicator circuit, encoder circuit and back light circuit.
synchronizing signal circuit, ACL circuit, buzzer circuit,
indicator circuit, encoder circuit and back light circuit.
1) LSI
This LSI controls the key strobe signal, relay driving
signal for oven function and indicator signal.
signal for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltage necessary in the
control unit.
control unit.
Symbol
Voltage
Application
VC
-5.2V
LSI(IC1)
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units
as shown in the touch control panel circuit.
as shown in the touch control panel circuit.
R32STM - 11
DESCRIPTION OF LSI
LSI(IZA988DR)
The I/O signal of the LSI(IZA988DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
ON/OFF time ratio in Micro
cooking
(a. 32second time base)
cooking
(a. 32second time base)
MICRO
ON
OFF
COOK
100%
100%
32sec.
0sec.
70%
24sec.
8sec.
50%
18sec.
14sec.
30%
12sec.
20sec.
10%
6sec.
26sec.
20 msec
During cooking
H
L
20 msec
H : GND
L (-5V)
A
B
0.12 sec
2.4 sec
1
C1
IN
Terminal not used.
2
VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
3-6
AN7-AN4
IN
Heating constant compensation terminal.
7
AN3
IN
Terminal not used.
8
AN2
IN
Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
Door opened; "L" level signal.
9-10
AN1-AN0
IN
Terminal not used.
11
P57
IN
Terminal not used.
12
P56
OUT
Signal to sound buzzer.
A: key touch sound.
B: Completion sound.
B: Completion sound.
13-18
P55-P50
IN/OUT
Terminal not used.
19
P47
OUT
Oven lamp, fan motor and turntable motor driving signal(Square Wave-
form : 50Hz).
form : 50Hz).
To turn on and off shut-off relay (RY1).
The square waveform voltage is deliv-
ered to the relay (RY1) driving circuit
and relay (RY2) control circuit.
The square waveform voltage is deliv-
ered to the relay (RY1) driving circuit
and relay (RY2) control circuit.
20
P46
IN/OUT
Terminal not used.
21
P45
OUT
Back light driving signal.
To change the brightness of the back light (Light emitting diodes LD1 - LD5). The
square waveform voltage is delivered to the back light driving circuit.
square waveform voltage is delivered to the back light driving circuit.
22
P44
OUT
Terminal not used.
23
P43
IN
Terminal not used.
24
INT0
IN
Signal to synchronized LSI with commercial power source frequency(50Hz).
This is basic timing for time processing of LSI.
25
P41
IN
Terminal not used.
26
P40
OUT
Terminal not used.
27-28
P77-P76
OUT
Terminal not used.
29
P75
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).
In 100% POWER operation, the signals
hold "L" level during microwave cooking
and "H" level while not cooking. In other
cooking modes (70%, 50%, 30%, 10%)
the signal turns to "H" level and "L" level
in repetition according to the power
level.
In 100% POWER operation, the signals
hold "L" level during microwave cooking
and "H" level while not cooking. In other
cooking modes (70%, 50%, 30%, 10%)
the signal turns to "H" level and "L" level
in repetition according to the power
level.
30-31
P74-P73
Terminal not used.
R32STM - 12
Pin No.
Signal
I/O
Description
32
P72
OUT
Terminal not used.
33
P71
IN
Terminal not used.
34
P70
IN
Connected to VC.
35
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Temporarily set to "L" level the moment power is applied, at this time the LSI is
reset. Thereafter set at "H" level.
Temporarily set to "L" level the moment power is applied, at this time the LSI is
reset. Thereafter set at "H" level.
36
XCIN
IN
Terminal not used.
37
XCOUT
OUT
Terminal not used.
38
XIN
IN
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XIN terminal.
with respect to XIN terminal.
39
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
40
VSS
IN
Power source voltage: -5V.
VC voltage of power source circuit input.
41-44
P27-P24
IN/OUT
Terminal not used.
45
P23
IN
Signal coming from touch key.
When any one of G2 line keys on key matrix is touched, a corresponding signal
from P11 - P17 will be input into P23. When no key is touched, the signal is held
at "L" level.
from P11 - P17 will be input into P23. When no key is touched, the signal is held
at "L" level.
46
P22
IN
Signal similar to P23.
When any one of G5 and G9 line keys on key matrix is touched, a corresponding
signal will be input into P22.
signal will be input into P22.
47
P21
IN
Signal similar to P23.
When any one of G7 line keys on key matrix is touched, a corresponding signal
will be input into P21.
will be input into P21.
48
P20
IN
Signal similar to P23.
When any one of G11 line keys on key matrix is touched, a corresponding signal
will be input into P20.
will be input into P20.
49
P17
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G12 line keys on matrix is touched.
while one of G12 line keys on matrix is touched.
50
P16
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G10 line keys on matrix is touched.
while one of G10 line keys on matrix is touched.
51
P15
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G8 line keys on matrix is touched.
while one of G8 line keys on matrix is touched.
52
P14
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G6 line keys on matrix is touched.
while one of G6 line keys on matrix is touched.
53
P13
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G4 line keys on matrix is touched.
while one of G4 line keys on matrix is touched.
54
P12
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G3 line keys on matrix is touched.
while one of G3 line keys on matrix is touched.
55
P11
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P20 - P23 terminal
while one of G1 line keys on matrix is touched.
while one of G1 line keys on matrix is touched.
DESCRIPTION OF LSI
LSI(IZA988DR)
The I/O signal of the LSI(IZA988DR) are detailed in the following table.
Click on the first or last page to see other R-32STM service manuals if exist.