Sharp R-249 Service Manual ▷ View online
R-249(SL)
R-249(W)
R-249(W)
11
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
g) The figure of all digits flicker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
b) Clock does not operate properly.
c) Cooking is not possible.
L
KEY UNIT TEST
1. CARRY OUT 3D CHECKS.
2. Isolate the key unit with the control panel frame to be tested.
3. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check
2. Isolate the key unit with the control panel frame to be tested.
3. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check
the circuit between the pins of the key unit that correspond to the STOP/CLEAR pad. When the
pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the
ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and
must be replaced. About the other pads, the above method may be used.
pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the
ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and
must be replaced. About the other pads, the above method may be used.
4. CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and normal
open terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and normal
open terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during 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. 14.0V D.C.
Oven lamp / Turntable motor / Cooling fan motor
RY2
Approx. 13.0V D.C.
High voltage transformer
CARRY OUT 4R CHECKS.
M
RELAY TEST
G4
G5
G6
G1
G8
G9
G10
G2
G3
G7
10sec
1min.
10min.
Express
COOK
START
AUTO
MINUTE
Express
DEFROST
STOP
CLEAR
POWER
WEIGHT
N
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD (PWB) IS OPEN
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.
on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide
given below for repair.
Pin
NO. G1
NO. G1
Pin
NO. G10
NO. G10
Key unit ribbon cable
Key unit (Membrane Switch) front view
R-249(SL)
R-249(W)
12
The touch control section consists of the following units as
shown in the touch control panel circuit.
shown in the touch control panel circuit.
(1) Key Unit (Membrane switch)
(2) Control Unit
(2) Control Unit
The principal functions of these units and their related
signals are explained below.
signals are explained below.
Key Unit (Membrane switch)
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through P24, P25, P26,
P31, P32 and P33.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P50 - P53
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 P24, P25, P26,
P31, P32 and P33.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P50 - P53
to perform the function that was requested.
Control Unit
Control unit consists of LSI, reset circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit and
synchronizing signal circuit.
Control unit consists of LSI, reset circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit and
synchronizing signal circuit.
1) Reset Circuit
This circuit generates a signal which resets the LSI to
the initial state when power is supplied.
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.
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
3) Power Source Circuit
This circuit generates voltage necessary in the control
unit from the AC line voltage. In addition, the synchro-
nizing signal is available in order to compose a basic
standard time in the clock circuit.
unit from the AC line voltage. In addition, the synchro-
nizing signal is available in order to compose a basic
standard time in the clock circuit.
Symbol
Voltage
Application
VSS
-5V
LSI(IC1)
4) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
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).
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.
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.
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
T1
a
b
c
d
(J1)
VRS1
RY2
RY1
CN-A
1
3
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
The rated voltage is not applied between Pin
1
No. 3 of the 2 pin connector (A) and the
Check supply voltage and oven power cord.
normal open terminal of the relay RY2.
2
The rated voltage is applied to primary side
Low voltage transformer or secondary circuit defective.
of low voltage transformer.
Check and replace control unit.
3
Only pattern at "a" is broken.
*Insert jumper wire J1 and solder.
4
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
NOTE: At the time of making these repairs, make
a visual inspection of the varistor. Check
for burned damage and examine the trans-
former with tester for the presence of
layer short-circuit (check primary coil re-
sistance). If any abnormal condition is
detected, replace the defective parts.
for burned damage and examine the trans-
former with tester for the presence of
layer short-circuit (check primary coil re-
sistance). If any abnormal condition is
detected, replace the defective parts.
CARRY OUT 4R CHECKS.
R-249(SL)
R-249(W)
R-249(W)
13
DESCRIPTION OF LSI
The I/O signal of the LSI are detailed in the following table.
Pin No.
Signal
I/O
Description
1
P50
IN
Signal coming from touch key.
When either G7 line on key matrix is touched, a corresponding signal out of P24 - P26 and
P31 - P33 will be input into P50. When no key is touched, the signal is held at “H” level.
When either G7 line on key matrix is touched, a corresponding signal out of P24 - P26 and
P31 - P33 will be input into P50. When no key is touched, the signal is held at “H” level.
2
P51
IN
Signal similar to P50.
When either G8 line on key matrix is touched, a corresponding signal will be input into P51.
When either G8 line on key matrix is touched, a corresponding signal will be input into P51.
3
P52
IN
Signal similar to P50.
When either G9 line on key matrix is touched, a corresponding signal will be input into P52.
When either G9 line on key matrix is touched, a corresponding signal will be input into P52.
4
P53
IN
Signal similar to P50.
When either G10 line on key matrix is touched, a corresponding signal will be input into P53.
When either G10 line on key matrix is touched, a corresponding signal will be input into P53.
5
IC
IN
Connected to VSS.
6
XT1
IN
Connected to VSS.
7
XT2
Terminal not used.
8
VDD
IN
Power source voltage input terminal.
The power souce voltage to drive the LSI. Connected to GND.
The power souce voltage to drive the LSI. Connected to GND.
9
VSS
IN
Power source voltage input terminal.
The power souce voltage to drive the LSI.
The power souce voltage to drive the LSI.
10
X1
IN
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the resistor-capacitor oscillation circuit
with respect to X2 terminal.
The internal clock frequency is set by inserting the resistor-capacitor oscillation circuit
with respect to X2 terminal.
11
X2
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of X1.
Output to control oscillation input of X1.
12
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Signal is input to reset the LSI to the initial state when power is applied.
13-15
P00-P02
OUT
Terminal not used.
16
P03
OUT
Terminal not used.
17
CAPH
_
Terminal not used.
18
CAPL
_
Terminal not used.
19-21
VLC0-VLC2
IN
Power source voltage input terminal.
Standard voltage for LCD.
Standard voltage for LCD.
22
COM0
OUT
Common data signal.
Connected to LCD signal COM0.
Connected to LCD signal COM0.
23
COM1
OUT
Common data signal.
Connected to LCD signal COM1.
Connected to LCD signal COM1.
24
COM2
OUT
Common data signal.
Connected to LCD signal COM2.
Connected to LCD signal COM2.
25
COM3
OUT
Terminal not used.
26-37
SEG0-SEG11
OUT
Segment data signal.
Connected to LCD.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (segment)
LSI signal (Pin No.)
LCD (segment)
SEG 0 (26) ................................... SEG 1
SEG 6 (32) .................................. SEG 7
SEG 1 (27) ................................... SEG 2
SEG 7 (33) ................................ SEG 8
SEG 2 (28) ................................... SEG 3
SEG 8 (34) ................................ SEG 9
SEG 3 (29) ................................... SEG 4
SEG 9 (35) .............................. SEG 10
SEG 4 (30) ................................... SEG 5
SEG 10 (36) .............................. SEG 11
SEG 5 (31) ................................... SEG 6
SEG 11 (37) .............................. SEG 12
38-40
SEG12-SEG14 OUT
Terminal not used.
R-249(SL)
R-249(W)
14
41
P70
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.
square waveform voltage is delivered to the
RY1 driving circuit and RY2 control circuit.
42
P71
OUT
Terminal not used.
43
P72
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2). 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.
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.
44
AVDD
IN
A/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI. Connected to GND.
The power source voltage to drive the A/D converter in the LSI. Connected to GND.
45-47
AIN5-AIN3
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.
48-50
AIN2-AIN0
IN
This is the terminal to detect the voltage of the signal coming from the touch key.
51
AVSS
IN
A/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI.
The power source voltage to drive the A/D converter in the LSI.
52
P11
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).
53
P10
OUT
Terminal not used.
54
P33
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G1 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G1 line keys on key matrix is touched.
55
P32
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G2 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G2 line keys on key matrix is touched.
56
P31
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G3 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G3 line keys on key matrix is touched.
57
INTP0
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
58
P26
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G4 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G4 line keys on key matrix is touched.
59
P25
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G5 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G5 line keys on key matrix is touched.
60
P24
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G6 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53
terminal while one of G6 line keys on key matrix is touched.
61
P23
OUT
Terminal not used.
62
P22
OUT
Terminal not used.
63
BZO90
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
64
P20
OUT
Terminal not used.
Pin No.
Signal
I/O
Description
20 msec.
During cooking
H : GND
L : -5V
Maximum
output
70% of maximum
output
H : GND
L : -5V
H : GND
L : -5V
ON
ON
OFF
OFF
OFF
24 sec.
8 sec.
20 msec.
H : GND
L : -5V
A
B
0.1 sec.
2.0 sec.
H : GND
L : -5V
H : GND
L : -5V
Click on the first or last page to see other R-249 service manuals if exist.