Sharp R-871M Service Manual ▷ View online
871M - 10
Pin No.
Signal
I/O
Description
ON
OFF
During
cooking
L
GND
H.
(Grill or dual)
(Convection or dual)
ON
OFF
During
cooking
L
GND
H.
ON
OFF
During
cooking
L
GND
H.
(Grill or dual)
ON
OFF
During cooking, or for 5 minutes or more
after grill cooking, convection cooking or
dual cooking
after grill cooking, convection cooking or
dual cooking
L
GND
H.
27
P77
OUT
Grill heating element (TOP GRILL) driving signal.
To turn on and off the grill heating
element relay (RY3). "L" level during
grill (TOP GRILL, TOP AND BOTTOM)
cooking, dual (MICRO + TOP) cooking
or convection cooking, "H" level
otherwise.
element relay (RY3). "L" level during
grill (TOP GRILL, TOP AND BOTTOM)
cooking, dual (MICRO + TOP) cooking
or convection cooking, "H" level
otherwise.
28
P76
OUT
Bottom heating element driving signal.
To turn on and off the bottom element
relay (RY4). "L" level during grill
(BOTTOM HEATER, TOP AND
BOTTOM) cooking, dual (MICRO +
BOTTOM) cooking or convection
cooking, "H" level otherwise.
relay (RY4). "L" level during grill
(BOTTOM HEATER, TOP AND
BOTTOM) cooking, dual (MICRO +
BOTTOM) cooking or convection
cooking, "H" level otherwise.
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.
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.
30-31
P74-P73
Terminal not used.
32
P72
OUT
Fan motor driving signal.
To turn on and off the fan motor
relay RY5. "L" level during
cooking, or for 5 minutes after grill
cooking or dual cooking. "H" level
otherwise.
relay RY5. "L" level during
cooking, or for 5 minutes after grill
cooking or dual cooking. "H" level
otherwise.
33
P71
IN
Convection motor driving signal.
To turn on and off shut-off relay
(RY6). "L" level during
CONVECTION; "H" level otherwise.
(RY6). "L" level during
CONVECTION; "H" level otherwise.
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.
circuit 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.
ON/OFF time ratio in Micro
cooking
(a. 32second time base)
cooking
(a. 32second time base)
ON/OFF time ratio in Micro
cooking
(a. 48second time base)
cooking
(a. 48second time base)
MICRO
ON
OFF
COOK
100%
100%
32sec.
0sec.
70%
24sec.
8sec.
50%
18sec.
14sec.
30%
12sec.
20sec.
10%
6sec.
26sec.
MICRO
ON
OFF
COOK
100%
100%
48sec.
0sec.
70%
36sec.
12sec.
50%
26sec.
22sec.
30%
16sec.
32sec.
10%
8sec.
40sec.
TOUCH CONTROL / DESCRIPTION OF LSI
871M - 11
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.
terminal 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.
terminal 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.
terminal 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.
terminal 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.
terminal 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.
terminal while one of G1 line keys on matrix is touched.
56
P10
OUT
Terminal not used.
57-60
SEG33-SEG30
OUT
Terminal not used.
61-90
SEG29-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (Pin No.)
LSI signal (Pin No.)
LCD (Pin No.)
SEG 0 (90) ................................ 1
SEG 0 (90) ................................ 1
SEG15 (75) ........................... 29
SEG 1 (89) ................................ 2
SEG16 (74) ........................... 28
SEG 2 (88) ................................ 3
SEG17 (73) ........................... 27
SEG 3 (87) ................................ 4
SEG18 (72) ........................... 26
SEG 4 (86) ................................ 5
SEG19 (71) ........................... 25
SEG 5 (85) ................................ 6
SEG20 (70) ........................... 24
SEG 6 (84) ................................ 7
SEG21 (69) ........................... 11
SEG 7 (83) ................................ 8
SEG22 (68) ........................... 23
SEG 8 (82) ................................ 9
SEG23 (67) ........................... 22
SEG 9 (81) .............................. 10
SEG24 (66) ........................... 12
SEG10 (80) ............................. 34
SEG25 (65) ........................... 13
SEG11 (79) ............................. 33
SEG26 (64) ........................... 14
SEG12 (78) ............................. 32
SEG27 (63) ........................... 15
SEG13 (77) ............................. 31
SEG28 (62) ........................... 16
SEG14 (76) ............................. 30
SEG29 (61) ........................... 17
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.
signal 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.
corresponding 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.
signal 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.
signal 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.
terminal while one of G12 line keys on matrix is touched.
Pin No.
Signal
I/O
Description
TOUCH CONTROL / DESCRIPTION OF LSI
871M - 12
TOUCH CONTROL / DESCRIPTION OF LSI
Pin No.
Signal
I/O
Description
91
VCC
IN
Connected to GND.
92
VREF
IN
Connected to GND.
93
AVSS
IN
Connected to VC.
94
COM3
OUT
Common data signal: COM3.
Connected to LCD (Pin No. 21).
95
COM2
OUT
Common data signal: COM2.
Connected to LCD (Pin No. 20).
96
COM1
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 19).
97
COM0
OUT
Common data signal: COM0.
Connected to LCD (Pin No. 18).
98-99
VL3-VL2
IN
Power source voltage input terminal.
Standard voltage for LCD.
100
C2
IN
Terminal not used.
871M - 13
TOUCH CONTROL / SERVICING
SERVICING
B.
On some models, the power supply cord between
the touch control panel and the oven proper is so
long enough that they may be separated from each
other. For those models, therefore, it is possible to
check and repair the 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
the dummy resistor(s) with resistance equal to that
of the controls are used.
long enough that they may be separated from each
other. For those models, therefore, it is possible to
check and repair the 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
the 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).
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
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
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.
electricity.
2) Connect the connector 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 abnormal
voltage due to static electricity etc. is not applied to the
input or output terminals.
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.
E
C B
Transistor
2SB1238
2SB1238
Transistor
DTA123ES
KRA101M
KRC243M
DTA123ES
KRA101M
KRC243M
E
C
B
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 electricity 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
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 electricity 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 PW boards containing
them in aluminium foil.
them in aluminium foil.
2) When soldering, ground the technician as shown in
the figure and use grounded soldering iron and work
table.
table.
approx. 1M ohm
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.
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
supply of the oven :
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING SERV-
ICING AND PRESENTS A HAZARD .
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING SERV-
ICING AND 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.
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.
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.
(sensor-related ones included) of the touch control
panel while keeping it connected to the oven.
Click on the first or last page to see other R-871M service manuals if exist.