R-464 (serv.man4). Control panel, component replacement and adjustment procedure - Sharp Home Appliance Service Manual (repair manual)

r-464 (serv.man4) service manual
Model
R-464 (serv.man4)
Pages
11
Size
126.3 KB
Type
PDF
Document
Service Manual
Brand
Device
Home Appliance / Microwave Oven / Control panel, component replacement and adjustment procedure
File
r-464-sm4.pdf
Date

Read Sharp R-464 (serv.man4) Service Manual online

R-464(SL)
13
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units.
(1) Key Unit
(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.
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 and P26.
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, synchro-
nizing 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.
2) Indicator Circuit
This circuit consists of 22 segments and 3 common
electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltages necessary in the con-
trol 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
-5V
LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, fan motors, turntable
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).
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.
7)  2nd. Interlock Relay Control 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- LD4).
R-464(SL)
14
Pin No.
Signal
I/O
Description
LSI
The I/O signal of the LSI is detailed in the following table.
1-2
VL2-VL1
IN
Power source voltage input terminal.
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.
7
AN3
OUT
Back light circuit (Light emitting diodes) driving signal.
8
AN2
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).
9-10
P61-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
Terminal not used.
16
P52
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 RY2 control circuit.
17-18
P51-P50
OUT
Terminal not used.
19
P47
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2). The
signals holds "L" level during microwave cook-
ing 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 100% and 70% power level.)
20
P46
IN
Signal coming from touch key.
When either G11 line on key matrix is touched, a corresponding signal out of P20 - P26
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 G10 line on key matrix is touched, a corresponding signal will be input into P45.
22
P44
IN
Signal similar to P46.
When either G9 line on key matrix is touched, a corresponding signal will be input into P44.
23
P43
IN
Signal similar to P46.
When either G8 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.
25
P41
OUT
Terminal not used.
26
P40
IN
Connected to GND through the pull-down resistor R100.
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.
28-29
P71-P70
OUT
Terminal not used.
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 XOUT terminal.
A
B
0.1 sec.
2.0 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-464(SL)
15
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
32
VSS
IN
Power source voltage: -5.0V.
VC voltage of power source circuit input.
33
P27
OUT
Terminal not used.
34
P26
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G7 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-P46 terminal while one
of G6 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-P46 terminal while one
of G5 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-P46 terminal while one
of G4 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-P46 terminal while one
of G3 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-P46 terminal while one
of G2 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-P46 terminal while one
of G1 line keys on key matrix is touched.
41-50
P17-P08
OUT
Terminal not used.
51-72
SEG21-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (Pin No.)
LSI signal (Pin No.)
LCD (Pin No.)
SEG 21 (51) ................... SEG21 ( 1)
SEG 10 (62) ................... SEG10 (12)
SEG 20 (52) ................... SEG20 ( 2)
SEG   9 (63) .................... SEG 9 (13)
SEG 19 (53) ................... SEG19 ( 3)
SEG   8 (64) .................... SEG 8 (14)
SEG 18 (54) ................... SEG18 ( 4)
SEG   7 (65) .................... SEG 7 (15)
SEG 17 (55) ................... SEG17 ( 5)
SEG   6 (66) .................... SEG 6 (16)
SEG 16 (56) ................... SEG16 ( 6)
SEG   5 (67) .................... SEG 5 (17)
SEG 15 (57) ................... SEG15 ( 7)
SEG   4 (68) .................... SEG 4 (18)
SEG 14 (58) ................... SEG14 ( 8)
SEG   3 (69) .................... SEG 3 (19)
SEG 13 (59) ................... SEG13 ( 9)
SEG   2 (70) .................... SEG 2 (20)
SEG 12 (60) .................. SEG12 (10)
SEG   1 (71) .................... SEG 1 (21)
SEG 11 (61) .................. SEG11 (11)
SEG   0 (72) .................... SEG 0 (22)
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: COM2.
Connected to LCD signal COM2.
78
COM1
OUT
Common data signal: COM1.
Connected to LCD signal COM1.
79
COM0
OUT
Common data signal: COM0.
Connected to LCD signal COM0.
80
VL3
IN
Power source voltage input terminal.
Standard voltage for LCD.
Pin No.
Signal
I/O
Description
R-464(SL)
16
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following
precautions should be strictly followed. CMOS LSI
have extremely high impedance at its input and output
terminals. For this reason, it is easily influenced by the
surrounding high voltage power source, static electric-
ity charge in clothes, etc. and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them
in aluminium foil. Also wrap all PW boards containing
them in aluminium foil.
2) When soldering, ground the technician as shown in the
figure and use grounded soldering iron and work table.
2. Shapes of Electronic Components
3. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so. To perform
the servicing, power to the touch control panel is
available either from the power line of the oven itself or
from an external power source.
(1) Servicing the touch control panel with power sup-
ply of the oven:
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE MI-
CROWAVE OVEN IS STILL LIVE DURING SERVIC-
ING PRESENTS A HAZARD.
Therefore, when checking the performance of the
touch control panel, put the outer cabinet on the oven
to avoid touching the high voltage transformer, or
unplug the primary terminal (connector) of the high
voltage transformer to turn it off; the end of such
connector must be insulated with an insulating tape.
After servicing, be sure to replace the leads to their
original locations.
A. On some models, the power supply cord between the
touch control panel and the oven itself is so short that
the two can’t be separated.
For those models, check and repair all the controls
(sensor-related ones included) of the touch control
panel while keeping it connected to the oven.
B. On some models, the power supply cord between the
touch control panel and the oven proper is long enough
that they may be separated from each other. For those
models, therefore, it is possible to check and repair the
TOUCH CONTROL PANEL SERVICING
controls of the touch control panel while keeping it
apart from the oven proper; in this case you must short
both ends of the door sensing switch (on PWB) of the
touch control panel with a jumper, which brings about
an operational state that is equivalent to the oven door
being closed. As for the sensor-related controls of the
touch control panel, checking them is possible if dummy
resistor(s) with resistance equal to that of the controls
are used.
(2) Servicing the touch control panel with power supply
from an external power source:
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect an
external power source to the power input terminal of
the touch control panel, then it is possible to check and
repair the controls of the touch control panel it is also
possible to check the sensor-related controls of the
touch control panel by using the dummy resistor(s).
4. Servicing Tools
Tools required to service the touch control panel
assembly.
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC-
10MHz type or more advanced model.
3) Others: Hand tools
5. Other Precautions
1) Before turning on the power source of the control unit,
remove the aluminium foil applied for preventing static
electricity.
2) Connect the connectors of the key unit to the control
unit being sure that the lead wires are not twisted.
3)  After aluminium foil is removed, be careful that abnor-
mal voltage due to static electricity etc. is not applied
to the input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to PWB,
making sure that all connections are tight.
5) Be sure to use specified components where high
precision is required.
approx. 1M ohm
E
C B
Transistor
DTA143ES
DTD143ES
Transistor
2SB1238
E
C
B
Page of 11
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