Sharp R-2277 Service Manual ▷ View online
19
R-2277
R-2287
R-2287
DESCRIPTION OF LSI
LSI(IZA648DR)
The I/O signal of the LSI(IZA648DR) is detailed in the following table.
The I/O signal of the LSI(IZA648DR) is detailed in the following table.
Pin No.
Signal
I/O
Description
1
VCC
IN
Connected to GND.
2
VEE
IN
Anode (segment) of Fluorescent Display light-up voltage: -35V.
Vp voltage of power source circuit input.
Vp voltage of power source circuit input.
3
AVSS
IN
Reference voltage input terminal.
A reference voltage applied to the A/D converter in the LSI. Connected to DC. (-5V)
A reference voltage applied to the A/D converter in the LSI. Connected to DC. (-5V)
4
VREF
IN
Reference voltage input terminal.
A reference voltage applied to the A/D converter in the LSI. Connected to GND.
A reference voltage applied to the A/D converter in the LSI. Connected to GND.
5-6
AN7-AN6
IN
Terminal to switch the specification.
7
AN5
IN
Temperature measurement input: INTAKE THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
8
AN4
IN
A/D input for troubleshooting Magnetron 1.
9
AN3
IN
A/D input for troubleshooting Magnetron 2.
10
AN2
IN
Temperature measurement input: EXHAUST THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
11
AN1
IN
Temperature measurement input: MAGNETRON THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
By inputting DC voltage corresponding to the temperature detected by the thermis-
tor, this input is converted into temperature by the A/D converter built into the LSI.
12
P60
IN
Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal (0V).
Door opened; "L" level signal (-5.0V).
Door opened; "L" level signal (-5.0V).
13
P55
OUT
Power supply output at thermistor detecting circuit.
(Output -5V in cooking only, but apply high impedance to others to prevent
thermistor from electrolytic corrosion ocurrence.)
(Output -5V in cooking only, but apply high impedance to others to prevent
thermistor from electrolytic corrosion ocurrence.)
14-16
P54-P52
OUT
Terminal not used.
17
P51
IN
Signal coming from switch unit.
When either one of switches SW2 and SW4 on the switch unit is pressed, a
corresponding signal out of P44 and P43 will be input into P51.
When either one of switches SW2 and SW4 on the switch unit is pressed, a
corresponding signal out of P44 and P43 will be input into P51.
18
P50
IN
Signal similar to P51.
When either one of switches SW1,SW3 and SW5 on the switch unit is pressed, a
corresponding signal out of P43,P44 and P45 will be input into P50.
When either one of switches SW1,SW3 and SW5 on the switch unit is pressed, a
corresponding signal out of P43,P44 and P45 will be input into P50.
19
P47
OUT
Signal to sound buzzer.
This signal is to control the 2.5kHz con-
tinuous signal.
tinuous signal.
A: Switch touch sound.
B: Completion sound.
B: Completion sound.
20
P46
OUT
Terminal not used.
21
P45
OUT
Switch strobe signal.
Signal is applied to the switch unit. A pulse signal is input to P50 terminal while
switch SW5 is pressed.
Signal is applied to the switch unit. A pulse signal is input to P50 terminal while
switch SW5 is pressed.
22
P44
OUT
Switch strobe signal.
Signal is applied to the switch unit. A pulse signal is input to P50 or P51 terminal
while switch SW3 or SW4 is pressed.
Signal is applied to the switch unit. A pulse signal is input to P50 or P51 terminal
while switch SW3 or SW4 is pressed.
23
P43
OUT
Switch strobe signal.
Signal is applied to the switch unit. A pulse signal is input to P50 or P51 terminal
while switch SW1 or SW2 is pressed.
Signal is applied to the switch unit. A pulse signal is input to P50 or P51 terminal
while switch SW1 or SW2 is pressed.
24
P42
IN
Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And pulse
signals are input into P42.
When the encoder is turned, the contacts of encoder make pulse signals. And pulse
signals are input into P42.
25
INT1
IN
Signal coming from encoder.
Signal similar to R42. Pulse signals are input into INT1.
Signal similar to R42. Pulse signals are input into INT1.
A
B
0.12 sec
1.2 sec
GND
-5V
1.2 sec
20
R-2277
R-2287
R-2287
26
INT0
IN
Signal synchronized with commercial power source freqency.
This is basic timing for all time processing of LSI.
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set to "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 to "L" level the moment power is supplied, 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 setting input.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XOUT terminal.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XOUT terminal.
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Output to control oscillation input of XIN.
32
VSS
IN
Power source voltage: -5V.
VC voltage of power source circuit input.
VC voltage of power source circuit input.
33
P27
OUT
Oven lamp, Blower motor and Stirrer motor driving signal (Square Wave-
form : 50Hz).
To turn on and off the shut-off relay (RY1).
The Square waveform voltage is delivered to
the RY1 relay driving circuit and relays
(RY2, RY3 COOK RELAY) control circuit.
form : 50Hz).
To turn on and off the shut-off relay (RY1).
The Square waveform voltage is delivered to
the RY1 relay driving circuit and relays
(RY2, RY3 COOK RELAY) control circuit.
34
P26
OUT
Terminal not used.
35-36
P25-P24
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay. In100% power level operation, "L" level during
cooking; "H" level otherwise. In other power level operation (50, 20, or 10%), "H"
and "L" level is repeated according to power level.
To turn on and off the cook relay. In100% power level operation, "L" level during
cooking; "H" level otherwise. In other power level operation (50, 20, or 10%), "H"
and "L" level is repeated according to power level.
P0WER LEVEL
ON
OFF
50%
26sec.
22sec.
20%
12sec.
36sec.
0%
8sec.
40sec.
37-38
P23-P22
OUT
Terminal not used.
39-48
P21-P10
OUT
Segment data signal.
The relation between signals and indicators are as follows:
Signal
Segment
Signal
Segment
P01 ................... i
P15 ..................... f
P00 ................ j,k
P14 ....................e
P21 ............... LB
P13 ....................d
P20 ............... UB
P12 .................... c
P17 .................. h
P11 ....................b
P16 .................. g
P10 ....................a
49-54
P07-P02
OUT
Digit selection signal.
The relation between digit signal and digit are as follows:
The relation between digit signal and digit are as follows:
Digit signal
Digit
P07
1st.
P06
2nd.
P05
3rd.
P04
4th.
P03
5th.
P02
6th.
Normally, one pulse is output in every ß
period, and input to the grid of the Fluores-
cent Display.
period, and input to the grid of the Fluores-
cent Display.
55-56
P01-P00
OUT
Segment data signal.
Pin No.
Signal
I/O
Description
GND
-5V
32 sec.
OFF
ON
H
L
20 msec
During cooking
GND
-5V
48 sec.
OFF
ON
ß(50Hz)
GND
VP
H
L
GND
VP
ß(50Hz)
P07
P06
P05
P04
P03
P02
GND
VP
21
R-2277
R-2287
R-2287
Pin No.
Signal
I/O
Description
Signal similar to P21.
57-64
P37-P30
OUT
Terminal not used.
22
R-2277
R-2287
R-2287
SERVICING
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 influ-
enced by the surrounding high voltage power source,
static electricity charge in clothes, etc, and some-
times it is not fully protected by the built-in protection
circuit.
In order to protect CMOS LSI.
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 influ-
enced by the surrounding high voltage power source,
static electricity charge in clothes, etc, and some-
times 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.
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
E
C B
E
C
B
E
C
B
T
i t
Transistor
2SA1561
2SA1561
2. Shapes of Electronic Components
and repair all the controls (sensor-related ones in-
cluded) of the touch control panel while keeping it
connected to the oven.
cluded) 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
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.
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
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 equiva-
lent to the oven door being closed. Connect an exter-
nal 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).
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is equiva-
lent to the oven door being closed. Connect an exter-
nal 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,
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 abnor-
mal voltage due to static electricity etc. is not applied
to the input or output terminals.
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.
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
SERVICING 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.
SERVICING 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
the two can’t be separated. For those models, check
Transistor
2SB953
2SB953
Transistor
DTA114YS
DTB143ES
DTD143ES
KRA101M
DTA114YS
DTB143ES
DTD143ES
KRA101M
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