Sharp R-212M (serv.man2) Service Manual ▷ View online
R-212M 13
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)
(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 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,
replace 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,
replace the defective parts.
CARRY OUT 4R CHECKS.
M
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN
BOARD(PWB) IS OPEN
(J1)
CN - A
a
b
c
d
1
5
1
P
T1
VRS1
RY1
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
R-212M 14
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit, encoder
circuit and indicator circuit.
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit, encoder
circuit and indicator circuit.
1) LSI
This LSI controls the encoder signal, tact switch strobe
signal, relay driving signal for oven function, buzzer
signal and LED signal.
signal, relay driving signal for oven function, buzzer
signal and LED signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
unit.
Symbol
Voltage
Application
VC
-5.0V
LSI(I-1)
VR
-12.0V
RELAY(RY1,2)
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 (tact switch touch sound and comple-
tion sound).
audible sounds (tact switch touch sound and comple-
tion 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) Encoder
The encoder generates the pulse signal, and the pulse
signal is sent to the LSI.
signal is sent to the LSI.
9) Indicator Circuit
Indicator elements are the Light-emitting diodes (LD1-
LD24 and LD30-LD34).
This circuit consists of 4-digits and 8 segments.
LD24 and LD30-LD34).
This circuit consists of 4-digits and 8 segments.
10) Tact Switch
Signal generated in the LSI is sent to the tact switch.
When a tact switch is touched, a signal is completed
through the tact switch and passed back to the LSI
through to perform the function that was requested.
When a tact switch is touched, a signal is completed
through the tact switch and passed back to the LSI
through to perform the function that was requested.
CONTROL PANEL ASSEMBLY
OUTLINE OF CONTROL PANEL
R-212M 15
1
D3
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD8, LD16 and LD24).
Signal is input to the cathodes of the light-emitting diodes (LD8, LD16 and LD24).
2
D4
OUT
Signal to sound buzzer.
A: Tact switch touch sound.
B: Completion sound.
A: Tact switch touch sound.
B: Completion sound.
3
D5
OUT
Oven lamp, turntable motor and fan motor driving signal(Square
Waveform : 50Hz).
To turn on and off shut-off relay
(RY1). The square waveform voltage
is delivered to the relay (RY1) driving
circuit and relay(RY2) control circuit.
Waveform : 50Hz).
To turn on and off shut-off relay
(RY1). The square waveform voltage
is delivered to the relay (RY1) driving
circuit and relay(RY2) control circuit.
4
D6
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.
5
D7
IN/OUT
Terminal not used.
6
P20
IN
Connected to 0V.
7
P21
IN
Signal coming from touch tact switch.
When tact switch SW2 is touched, a signal will be input into P21. When tact switch
is not touched, the signal is held at "H" level.
When tact switch SW2 is touched, a signal will be input into P21. When tact switch
is not touched, the signal is held at "H" level.
8
P22
IN
Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into P22.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into P22.
9
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.
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.
10
CNVSS
IN
Reference voltage input terminal.
A reference voltage is applied to the A/D converter in the LSI. Connected to VC.
A reference voltage is applied to the A/D converter in the LSI. Connected to VC.
11
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
Output to control oscillation input of XOUT.
12
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.
13
VSS
IN
Power source voltage: -5V.
The power source voltage to drive the LSI is input to VSS terminal. Connected to
VC.
The power source voltage to drive the LSI is input to VSS terminal. Connected to
VC.
14
VDD
IN
Power source voltage: 0V.
The power source voltage to drive the LSI is input to VDD terminal.
The power source voltage to drive the LSI is input to VDD terminal.
15
N.F
IN
Connected to VSS terminal.
16
INT0
IN
Signal coming from encoder.
Signal similar to INT0. Pulse signals are input into INT0.
Signal similar to INT0. Pulse signals are input into INT0.
DESCRIPTION OF LSI
LSI(IZA948DR)
The I/O signal of the LSI(IZA948DR) are detailed in the following table.
The I/O signal of the LSI(IZA948DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
ON/OFF time ratio in Mi-
cro cooking
(a. 27second time base)
cro cooking
(a. 27second time base)
MICRO
ON
OFF
COOK
100%
27sec.
0sec.
70%
21sec.
6sec.
50%
15sec.
12sec.
30%
9sec.
18sec.
10%
5sec.
22sec.
A
B
H: GND
L: -5V
0.12 sec
2.4 sec
20 msec
During cooking
H
L
R-212M 16
DESCRIPTION OF LSI
LSI(IZA948DR)
The I/O signal of the LSI(IZA948DR) are detailed in the following table.
The I/O signal of the LSI(IZA948DR) are detailed in the following table.
17
INT1
IN
Signal to synchronize LSI with commercial power source frequency.
This is basic timing for all real time
processing of LSI.
This is basic timing for all real time
processing of LSI.
18-19
AIN0-AIN1
IN
Terminal to change functions according to the model.
Signal in accordance with the model in operation is applied to set up its function.
Signal in accordance with the model in operation is applied to set up its function.
20
AIN2
IN
Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
Door closed; "H" level signal.
Door opened; "L" level signal.
21
AIN3
IN
Terminal to change functions according to the model.
Signal in accordance with the model in operation is applied to set up its function.
Signal in accordance with the model in operation is applied to set up its function.
22
P00
OUT
Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD30 - LD34).
Signal is input to the anodes of the light-emitting diodes (LD30 - LD34).
23
P01
OUT
Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD9 - LD16).
Signal is input to the anodes of the light-emitting diodes (LD9 - LD16).
24
P02
OUT
Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD17 - LD24).
Signal is input to the anodes of the light-emitting diodes (LD17 - LD24).
25
P03
OUT
Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD1 - LD8).
Signal is input to the anodes of the light-emitting diodes (LD1 - LD8).
26
P10
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD1, LD9, LD17 and
LD30).
Signal is input to the cathodes of the light-emitting diodes (LD1, LD9, LD17 and
LD30).
27
P11
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD2, LD10, LD18 and
LD31).
Signal is input to the cathodes of the light-emitting diodes (LD2, LD10, LD18 and
LD31).
28
P12
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD3, LD11, LD19 and
LD32).
Signal is input to the cathodes of the light-emitting diodes (LD3, LD11, LD19 and
LD32).
29
P13
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD4, LD12 and LD20).
Signal is input to the cathodes of the light-emitting diodes (LD4, LD12 and LD20).
30
D0
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD5, LD13, LD21 and
LD33).
Signal is input to the cathodes of the light-emitting diodes (LD5, LD13, LD21 and
LD33).
31
D1
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD6, LD14, LD22 and
LD34).
Signal is input to the cathodes of the light-emitting diodes (LD6, LD14, LD22 and
LD34).
32
D2
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD7, LD15 and LD23).
Signal is input to the cathodes of the light-emitting diodes (LD7, LD15 and LD23).
Pin No.
Signal
I/O
Description
20 msec
H : GND
L (-5V)
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