Sharp R-252M (serv.man2) Service Manual ▷ View online
R-252M 13
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
1. CARRY OUT 3D CHECKS.
2. Disconnect the leads from the primary of the high voltage transformer. Make sure that the leads
2. Disconnect the leads from the primary of the high voltage transformer. Make sure that the leads
remain isolated from other oven components and chassis. (Use insulation tape if necessary.)
3. Close the door.
4. Reconnect the supply.
5. Check the voltage between Pin Nos. 1 and 3 of the 3 pin connector (A) on the control unit with an
4. Reconnect the supply.
5. Check the voltage between Pin Nos. 1 and 3 of the 3 pin connector (A) on the control unit with an
A.C. voltmeter. The meter should indicate 230-240 volts, if not check oven circuit.
6. RY1 and RY3 TEST
These are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during
the microwave cooking operation.
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
RY3
APPROX. 18.0V D.C.
High voltage transformer
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.
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)
(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 burn-
ing damage and examine the transformer
with tester for the presence of layer short-
circuit (check primary coil resistance). If
any abnormal condition is detected, re-
place the defective parts.
ing damage and examine the transformer
with tester for the presence of layer short-
circuit (check primary coil resistance). If
any abnormal condition is detected, re-
place the defective parts.
CARRY OUT 4R CHECKS.
M
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED
WIRING BOARD (PWB) IS OPEN
WIRING BOARD (PWB) IS OPEN
3
1
RY1
(J1)
a
b
c
d
VRS1
T1
CN - A
L
RELAY TEST
R-252M 14
The touch control section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power
(2) Control Unit (The Control Unit consists of Power
Unit and CPU Unit).
The principal functions of these units and the signals
communicated among them are explained below.
communicated 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 through P20, P21,
P22, P23, P24, P25, P26 and P27.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through P43, P44, P45 and P46 to perform the function
that was requested.
The key unit is composed of a matrix, signals generated
in the LSI are sent to the key unit through P20, P21,
P22, P23, P24, P25, P26 and P27.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through P43, P44, P45 and P46 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,
synchronizing signal circuit and back light circuit.
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit,
synchronizing 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.
to the 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 voltages 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.
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.
Symbol
Voltage
Application
VC
-5.2V
LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, fan motor, turntable
motor and light the oven lamp.
motor and light the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and
completion sound).
emit audible sounds (key 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.
in order to compose a basic standard time in the
clock circuit.
It accompanies a very small error because it works
on commercial frequency.
7) Door Sensing Switch (Stop Switch)
A switch to “tell” the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1- LD5).
LD1- LD5).
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
R-252M 15
1-2
VL2-VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
Standard voltage for LCD.
3-6
AN7-AN4
IN
Terminal to change cooking input 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 cooking constant.
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 cooking constant.
7-8
P63-P62
OUT
Terminal not used.
9
AN1
IN
To input signal which communicates the door open/close information to LSI.
Door close "H" level signal (0V). Door open "L" level signal (-5V).
Door close "H" level signal (0V). Door open "L" level signal (-5V).
10
P60
OUT
Terminal not used.
11-13
P57-P55
OUT
Terminal not used.
14
CNTR0
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
15
P53
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 and RY3 control
circuit.
The square waveform voltage is delivered
to the RY1 driving circuit and RY3 control
circuit.
16
P52
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY3).
The signals holds "L" level during
microwave cooking and "H" level while
not cooking. In other cooking modes
(variable cooking) the signal turns to "H"
level and "L" level in repetition according
to the power level.
To turn on and off the cook relay (RY3).
The signals holds "L" level during
microwave cooking and "H" level while
not cooking. In other cooking modes
(variable cooking) the signal turns to "H"
level and "L" level in repetition according
to the power level.
(ON and OFF times for other power level.)
17-18
P51-P50
OUT
Terminal not used.
19
P47
OUT
Terminal not used.
20
P46
IN
Signal coming from touch key.
When either G12 line on key matrix is touched, a corresponding signal out of P20
- P27 will be input into P46. When no key is touched, the signal is held at "H" level.
When either G12 line on key matrix is touched, a corresponding signal out of P20
- P27 will be input into P46. When no key is touched, the signal is held at "H" level.
21
P45
IN
Signal similar to P46.
When either G11 line on key matrix is touched, a corresponding signal will be input
into P45.
When either G11 line on key matrix is touched, a corresponding signal will be input
into P45.
22
P44
IN
Signal similar to P46.
When either G10 line on key matrix is touched, a corresponding signal will be input
into P44.
When either G10 line on key matrix is touched, a corresponding signal will be input
into P44.
23
P43
IN
Signal similar to P46.
When either G9 line on key matrix is touched, a corresponding signal will be input
into P43.
When either G9 line on key matrix is touched, a corresponding signal will be input
into P43.
24
INT0
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing
of LSI.
of LSI.
25
P41
OUT
Terminal not used.
26
P40
IN
Connected to VC through the pull-down resistor R90.
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied. Temporarily
set "L" level the moment power is applied, 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 applied. Temporarily
set "L" level the moment power is applied, at this time the LSI is reset. Thereafter
set at "H" level.
28-29
P71-P70
OUT
Terminal not used.
DESCRIPTION OF LSI
LSI(IZA954DR)
The I/O signal of the LSI(IZA954DR) are detailed in the following table.
The I/O signal of the LSI(IZA954DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
A
B
0.12 sec.
2.4 sec.
H : GND
L : -5V
H : GND
L : -5V
20.0 msec.
During cooking
H : GND
L : -5V
100P
H : GND
L : -5V
H : GND
L : -5V
70P
ON
ON
OFF
OFF
OFF
24 sec.
8 sec.
20.0 msec.
H : GND
L : -5V
R-252M 16
Pin No.
Signal
I/O
Description
30
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.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XIN terminal.
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
Output to control oscillation input of XOUT.
32
VSS
IN
Power source voltage: -5.0V.
VC voltage of power source circuit input.
VC voltage of power source circuit input.
33
P27
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G1 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G1 line keys on key matrix is touched.
34
P26
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G2 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G2 line keys on key matrix is touched.
35
P25
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G3 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G3 line keys on key matrix is touched.
36
P24
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G4 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G4 line keys on key matrix is touched.
37
P23
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G5 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G5 line keys on key matrix is touched.
38
P22
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G6 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G6 line keys on key matrix is touched.
39
P21
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G7 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G7 line keys on key matrix is touched.
40
P20
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G8 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G8 line keys on key matrix is touched.
41-56
P17-P00
OUT
Terminal not used.
57-60
P37-P34
OUT
Terminal not used.
61-72
SEG11-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.) LCD (Pin No.)
The relation between signals are as follows:
LSI signal (Pin No.) LCD (Pin No.)
LSI signal (Pin No.) LCD (Pin No.)
SEG 11 (61) ............................ S12
SEG 5 (67) .............................. S6
SEG 10 (62) ............................ S11
SEG 4 (68) .............................. S5
SEG 9 (63) ............................ S10
SEG 3 (69) .............................. S4
SEG 8 (64) ............................ S9
SEG 2 (70) .............................. S3
SEG 7 (65) ............................ S8
SEG 1 (71) .............................. S2
SEG 6 (66) ............................ S7
SEG 0 (72) .............................. S1
73/74
VCC/VREF
IN
Connected to GND.
75
AVSS
IN
Connected to VC.
76
COM3
OUT
Terminal not used.
77
COM2
OUT
Common data signal.
Connected to LCD signal C3.
78
COM1
OUT
Common data signal.
Connected to LCD signal C2.
79
COM0
OUT
Common data signal.
Connected to LCD signal C1.
80
VL3
IN
Power source voltage input terminal.
Standard voltage for LCD.
DESCRIPTION OF LSI
LSI(IZA954DR)
The I/O signal of the LSI(IZA954DR) are detailed in the following table.
The I/O signal of the LSI(IZA954DR) are detailed in the following table.
Click on the first or last page to see other R-252M (serv.man2) service manuals if exist.