Sharp R-555 Service Manual ▷ View online
R-555(SL)
11
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
M
RELAY TEST
Remove the outer case and check voltage between Pin No 1 of the 2-pin connector (A) and the normal
open terminal of the relay RY1 on the power unit with an A.C. voltmeter. The meter should indicate
230 - 240 volts, if not check oven circuit.
open terminal of the relay RY1 on the power 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. 12V D.C.
Oven lamp / Turntable motor / Cooling fan motor
RY2
APPROX. 12V D.C.
Power transformer
CARRY OUT 4R CHECKS.
L
KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable
is making good contact, verify that the 2nd. Interlock Relay Control Switch operates properly; that is
the contacts are closed when the door is closed and open when the door is open.
If the 2nd. Interlock Relay Control Switch is good, disconnect the flat ribbon cable that connects the
key unit to the control unit and make sure the 2nd. Interlock Relay Control Switch is closed (either
close the door or short the 2nd. Interlock Relay Control Switch connector). Use the key unit matrix
indicated on the control panel schematic and place a jumper wire between the pins that correspond
to the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a
beep the key unit is faulty and must be replaced. If the control unit does not respond, it is faulty and
must be replaced.
If a specific pad does not respond, the above method may be used (after clearing the control unit) to
determine if the control unit or key pad is at fault.
is making good contact, verify that the 2nd. Interlock Relay Control Switch operates properly; that is
the contacts are closed when the door is closed and open when the door is open.
If the 2nd. Interlock Relay Control Switch is good, disconnect the flat ribbon cable that connects the
key unit to the control unit and make sure the 2nd. Interlock Relay Control Switch is closed (either
close the door or short the 2nd. Interlock Relay Control Switch connector). Use the key unit matrix
indicated on the control panel schematic and place a jumper wire between the pins that correspond
to the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a
beep the key unit is faulty and must be replaced. If the control unit does not respond, it is faulty and
must be replaced.
If a specific pad does not respond, the above method may be used (after clearing the control unit) to
determine if the control unit or key pad is at fault.
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.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
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.
N
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
(PWB) IS OPEN
G 9
G 8
G 7
G 6
G 5
G 4
G 3
G 2
G 1
G10
G11
G12
G13
G14
Roast
Poultry
Roast Pork
Whole
Poultry
Meat
Joint
Joint
Roast
Beef/Lamb
Chicken
Quarters
More
Risotto
Pasta Dish
Stop
Clear
10Sec.
1Min.
10Min.
Delay Start
Clock Set
Up
Kitchen
Timer
Less
Down
Start Auto
Minute
Auto
Cook
Power
Level
Casserole
Kg/Lb
Conversion
R-555(SL)
12
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
STEPS
OCCURRENCE
CAUSE OR CORRECTION
The rated AC voltage is not present between
1
Pin No. 1 of the 2-pin connector (A) and the
Check supply voltage and oven power cord.
normal open terminal of the relay RY1.
2
The rated AC voltage is present to 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.
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 exam-
ine the transformer with a tester for the
presence of layer short-circuit (check
the primary coil resistance). If any ab-
normal condition is detected, replace
the defective parts.
Check for burned damage and exam-
ine the transformer with a tester for the
presence of layer short-circuit (check
the primary coil resistance). If any ab-
normal condition is detected, replace
the defective parts.
CARRY OUT 4R CHECKS.
T1
P
13
VRS1
(J1)
b
d
c
a
a
R-555(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.
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, P26 and P27.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P41, P43,
P44, P45 and AN2 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 P20, P21, P22,
P23, P24, P25, P26 and P27.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P41, P43,
P44, P45 and AN2 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, synchro-
nizing signal circuit and back light circuit.
Control unit consists of LSI, reset circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchro-
nizing signal circuit and back light 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 22 segments and 3 common
electrodes using a Liquid Crystal Display.
electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltages necessary in the control
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.
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 motor, turntable
motor and light the oven lamp.
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).
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.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1- LD4).
LD1- LD4).
R-555(SL)
14
1-2
VL2-VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
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.
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
P63
OUT
Terminal not used.
8
AN2
IN
Input terminal to judge the model.
The one of signals P20-P27 will be input into AN2 through one of G1-G8 lines on key
matrix. The LSI will judge the model by this signal.
The one of signals P20-P27 will be input into AN2 through one of G1-G8 lines on key
matrix. The LSI will judge the model by this signal.
9
AN1
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).
10
AN0
IN
Input terminal to judge the model.
Connected to GND through the pull-down resistor.
Connected to GND through the pull-down resistor.
11
P57
OUT
Back light circuit (Light emitting diodes) driving signal.
12-13
P56-P55
OUT
Terminal not used.
14
CNTR0
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
A: key touch sound.
B: Completion sound.
15
P53
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.
To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to the
RY1 driving circuit and RY2 control circuit.
16
P52
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.
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 other power level.)
17-18
P51-P50
OUT
Terminal not used.
19-20
P47-P46
OUT
Terminal not used.
21
P45
IN
Signal coming from touch key.
When either G12 line on key matrix is touched, a corresponding signal out of P20-P27 will
be input into P45. When no key is touched, the signal is held at “H” level.
When either G12 line on key matrix is touched, a corresponding signal out of P20-P27 will
be input into P45. When no key is touched, the signal is held at “H” level.
22
P44
IN
Signal similar to P45.
When either G11 line on key matrix is touched, a corresponding signal will be input into P44.
When either G11 line on key matrix is touched, a corresponding signal will be input into P44.
23
P43
IN
Signal similar to P45.
When either G10 line on key matrix is touched, a corresponding signal will be input into P43.
When either G10 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.
This is the basic timing for time processing of LSI.
25
P41
IN
Signal similar to P45.
When either G9 line on key matrix is touched, a corresponding signal will be input into P41.
When either G9 line on key matrix is touched, a corresponding signal will be input into P41.
26
P40
IN
Connected to GND through the pull-down resistor R90.
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.
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.
LSI
The I/O signal of the LSI is detailed in the following table.
The I/O signal of the LSI is detailed in the following table.
Pin No.
Signal
I/O
Description
20.0 msec.
During cooking
H : GND
L : -5V
20.0 msec.
H : GND
L : -5V
A
B
0.1 sec.
2.0 sec.
H : GND
L : -5V
H : GND
L : -5V
100P
H : GND
L : -5V
H : GND
L : -5V
70P
ON
ON
OFF
OFF
OFF
24 sec.
8 sec.
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