Sharp R-82FBSTM (serv.man2) Service Manual ▷ View online
R-82FBSTM - 17
M
CONTROL PANEL ASSEMBLY TEST
The control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike
conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, the control panel assembly is divided into two units, Control Unit and Jog switch
Unit, and also the control unit is divided into two units, CPU unit and Power unit, and troubleshooting
by replacement is described according to the symptoms indicated.
1. Jog switch Unit Note : Check Jog switch unit wire harness connection before replacement.
conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, the control panel assembly is divided into two units, Control Unit and Jog switch
Unit, and also the control unit is divided into two units, CPU unit and Power unit, and troubleshooting
by replacement is described according to the symptoms indicated.
1. Jog switch Unit Note : Check Jog switch unit wire harness connection before replacement.
The following symptoms indicate a defective Jog switch unit. Replace the Jog switch unit.
1-1. Tact switch
a) When touching the buttons, a certain button produces no signal at all.
b) When touching the buttons, sometimes a button produces no signal.
b) When touching the buttons, sometimes a button produces no signal.
1-2. Potentiometer
a) When rotating the potentiometer, the cooking mode can not be selected.
1-3. Encoder
a) When rotating the encoder, the cooking time or the weight of food can not be entered.
2. Control Panel
The following symptoms indicate a defective control unit. Before replacing the control unit,
perform the Jog switch unit test (Procedure N) to determine if control unit is faulty.
perform the Jog switch unit test (Procedure N) to determine if control unit is faulty.
2-1 In connection with buttons
a) When touching the buttons, a certain group of buttons do not produce a signal.
b) When touching the buttons, no buttons produce a signal.
b) When touching the buttons, no buttons produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light up.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
b) At a certain digit, brightness is low.
c) Only one indicator does not light up.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible troubles 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.
d) Proper temperature measurement is not obtained.
b) Clock does not operate properly.
c) Cooking is not possible.
d) Proper temperature measurement is not obtained.
PROCEDURE
LETTER
COMPONENT TEST
TEST PROCEDURES
N
KEY AND JOG UNIT TEST
If the display fails to clear when the STOP button is depressed, first verify the cable is making good
contact, verify that the stop switch operates properly; that the contacts are closed when the door is
closed and open when the door is open. If the stop switch is good, disconnect the cable that connects
the Jog switch unit to the control unit and make sure the stop switch is closed (either close the door
or short the stop switch connector). Use the Jog switch unit matrix indicated on the control panel
schematic and place a jumper wire between the pins that correspond to the STOP button making
momentary contact. If the control unit responds by clearing with a beep the Jog switch unit is faulty and
must be replaced. If the control unit does not respond, it is faulty and must be replaced. If a specific
button does not respond, the above method may be used (after clearing the control unit) to determine
if the control unit or Jog switch unit is at fault.
CARRY OUT 4R CHECKS.
contact, verify that the stop switch operates properly; that the contacts are closed when the door is
closed and open when the door is open. If the stop switch is good, disconnect the cable that connects
the Jog switch unit to the control unit and make sure the stop switch is closed (either close the door
or short the stop switch connector). Use the Jog switch unit matrix indicated on the control panel
schematic and place a jumper wire between the pins that correspond to the STOP button making
momentary contact. If the control unit responds by clearing with a beep the Jog switch unit is faulty and
must be replaced. If the control unit does not respond, it is faulty and must be replaced. If a specific
button does not respond, the above method may be used (after clearing the control unit) to determine
if the control unit or Jog switch unit is at fault.
CARRY OUT 4R CHECKS.
J-6
J-3
J-3
J-4
J-7
J-8
J-4
J-7
J-8
J-5
J-2
J-1
J-6
J-5
J-2
J-1
SW11
SW12
SW13
SW9
SW10
SW5
SW4
SW7
SW1
SW2
SW3
STOP
POWER
AUTO
SW8
SW6
HELP
R-82FBSTM - 18
PROCEDURE
LETTER
COMPONENT TEST
P
PROCEDURES TO BE TAKEN WITH THE FOIL PATTERN ON THE PRINTED WIRING
control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
The meter should indicate 230-240 volts, if not check oven circuit.
Relay Test
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, grill
operation, convection operation or dual operation.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, grill
operation, convection operation or dual 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. 18.0V D.C.
Oven lamp / Turntable motor
RY2
Approx. 18.0V D.C.
High voltage transformer
RY3
Approx. 24.0V D.C.
Grill (Top) heating element
RY4
Approx. 24.0V D.C.
Bottom heating element
RY5
Approx. 24.0V D.C.
Touch control transformer
RY6
Approx. 24.0V D.C.
Fan motor
RY7
Approx. 24.0V D.C.
Convection motor
CARRY OUT 4R CHECKS..
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 between
Check supply voltage and oven power cord.
Pin Nos. 1 and 3 of the 4-pin connector (E).
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 burning dam-
age and examine the transformer with tester
for the presence of layer short circuit (check
primary coil resistance).
age and examine the transformer with tester
for the presence of layer short circuit (check
primary coil resistance).
If any abnormal condition is detected, re-
place the defective parts.
place the defective parts.
CARRY OUT 4R CHECKS.
CN-A
CN-E
D12
7
(J1)
D13
VRS1
a
c
d
b
TEST PROCEDURES
O
RELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 4 pin connector (E) on the
R-82FBSTM - 19
CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units
as shown in the touch control panel circuit.
as shown in the touch control panel circuit.
(1) Jog Switch Unit
(2) Control Unit (The Control unit consists of Power unit
(2) Control Unit (The Control unit consists of Power unit
and CPU unit.)
The principal functions of these units and signals commu-
nicated among them are explained below.
nicated among them are explained below.
Jog Switch Unit
The jog switch unit is composed of a matrix, signals
generated in the LSI are sent to the jog switch unit from
P40, P41, P76 and P77.
When a button is touched, a signal is completed through
the jog switch unit and passed back to the LSI through P50
- P53 to perform the function that was requested.
The jog switch unit is composed of a matrix, signals
generated in the LSI are sent to the jog switch unit from
P40, P41, P76 and P77.
When a button is touched, a signal is completed through
the jog switch unit and passed back to the LSI through P50
- P53 to perform the function that was requested.
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, reset circuit, buzzer circuit, indicator
circuit, encoder circuit,potentiometer circuit, temperature
measurement circuit and back light circuit.
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, reset circuit, buzzer circuit, indicator
circuit, encoder circuit,potentiometer circuit, temperature
measurement circuit and back light circuit.
1) LSI
This LSI controls the temperature measurement sig-
nal, tact switch strobe signal, relay driving signal for
oven function and indicator signal.
nal, tact switch strobe signal, relay driving signal for
oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
unit.
Symbol
Voltage
Application
VC
-5.2V
LSI(IC1)
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) Reset Circuit
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) Stop Switch
A switch to “tell” the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, top and bottom heating ele-
ment, convection motor, fan motor, turntable motor,
touch control transformer and light the oven lamp.
ment, convection motor, fan motor, turntable motor,
touch control transformer and light the oven lamp.
8) Encoder
The encoder converts the signal generated by LSI into
the pulse signal, and the pulse signal is returned to the
LSI.
the pulse signal, and the pulse signal is returned to the
LSI.
9) Potentiometer Circuit
The circuit makes setting of the cooking mode by
variable resistance.
variable resistance.
10) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1 - LD10).
LD1 - LD10).
11) Indicator Circuit
This circuit consists 7-digits, 39-segments and 3-com-
mon electrodes using a Liquid Crystal Display.
mon electrodes using a Liquid Crystal Display.
12)Temperature Measurement Circuit : (OVEN THER-
MISTOR)
The temperature in the oven cavity is sensed by the
thermistor. The variation of resistance according to
sensed temperature is detected by the temperature
measurement circuit and the result applied to LSI. The
LSI uses this information to control the relay and
display units.
thermistor. The variation of resistance according to
sensed temperature is detected by the temperature
measurement circuit and the result applied to LSI. The
LSI uses this information to control the relay and
display units.
R-82FBSTM - 20
8
AN2
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.
9
AN1
IN
Heating constant compensation terminal.
10
AN0
IN
Terminal to change functions to the Models.
11
P57
OUT
Timing signal output terminal for temperature measurement(OVEN
THERMISTOR).
“H” level (GND) : Thermistor OPEN timing.
“L” level (-5V) : Temperature measuring timing. (Oven cooking)
THERMISTOR).
“H” level (GND) : Thermistor OPEN timing.
“L” level (-5V) : Temperature measuring timing. (Oven cooking)
12
P56
OUT
Terminal not used.
13
P55
OUT
Timing signal output terminal for temperature measurement(OVEN
THERMISTOR).
“H” level (GND) : Thermistor OPEN timing.
“L” level (-5V) : Temperature measuring timing. (Oven cooking)
THERMISTOR).
“H” level (GND) : Thermistor OPEN timing.
“L” level (-5V) : Temperature measuring timing. (Oven cooking)
14
P54
OUT
Terminal not used.
15
P53
IN
Signal coming from touch key.
When any one of G12 line keys on key matrix is touched, a corresponding signal
from P40, P41, P72, P73, P74, P75, P76 and P77 will be input into P53. When no
key is touched, the signal is held at “L” level.
When any one of G12 line keys on key matrix is touched, a corresponding signal
from P40, P41, P72, P73, P74, P75, P76 and P77 will be input into P53. When no
key is touched, the signal is held at “L” level.
16
P52
IN
Signal similar to P53.
When any one of G11 line keys on key matrix is touched, a corresponding signal
will be input into P52.
When any one of G11 line keys on key matrix is touched, a corresponding signal
will be input into P52.
17
P51
IN
Signal similar to P53.
When any one of G10 line keys on key matrix is touched, a corresponding signal
will be input into P51.
will be input into P51.
18
P50
IN
Signal similar to P53.
When any one of G9 line keys on key matrix is touched, a corresponding signal will
be input into P50.
When any one of G9 line keys on key matrix is touched, a corresponding signal will
be input into P50.
19-22
P47-P44
IN/OUT
Terminal not used.
23
TOUT
OUT
Signal to sound buzzer.
A: Tact switch touch sound.
B: Completion sound.
C: When the temperature of the oven cavity
A: Tact switch touch sound.
B: Completion sound.
C: When the temperature of the oven cavity
reaches the preset temperature in the
preheating mode, or when the
preheating hold time (30 minutes) is
elapsed.
preheating mode, or when the
preheating hold time (30 minutes) is
elapsed.
24
INT2
IN
Signal to synchronized LSI with commercial power source frequency(50Hz).
This is basic timing for time processing of LSI.
This is basic timing for time processing of LSI.
25
P41
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50-P53 terminal
while one of G8 line key on matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P50-P53 terminal
while one of G8 line key on matrix is touched.
A
B
C
H : GND
L
0.1 sec.
2.0 sec.
1.0 sec.
1.0 sec.
20 msec.
H : GND
L (-5V)
Pin No.
Signal
I/O
Description
DESCRIPTION OF LSI
The I/O signal of the LSI are detailed in the following table.
1
C1
IN
Terminal not used.
2
VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
Standard voltage for LCD.
3
AN7
IN
Terminal to change the on timing of the cook relay (RY2).
4-5
AN6-AN5
IN
Heating constant compensation terminal.
6
AN4
OUT
Terminal not used.
7
AN3
IN
Temperature measurement input: OVEN THERMISTOR.
By inputting DC voltage corresponding to the temperature detected by the
thermistor, this input is converted into the temperature by the A/D converter built
into the LSI.
By inputting DC voltage corresponding to the temperature detected by the
thermistor, this input is converted into the temperature by the A/D converter built
into the LSI.
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