Sharp R-464 (serv.man2) Service Manual ▷ View online
R-464(SL)
10
CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and high voltage fuse.
Check them and replace the defective parts and high voltage fuse.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE THE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE RE-
PLACEMENT
K
HIGH VOLTAGE FUSE TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a
voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided into two
units, Control Unit and Key Unit, and also the Control Unit is divided into two units, CPU Unit and
Power Unit, and troubleshooting by unit replacement is described according to the symptoms
indicated.
unlike conventional microwave ovens, proper maintenance cannot be performed with only a
voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided into two
units, Control Unit and Key Unit, and also the Control Unit is divided into two units, CPU Unit and
Power Unit, and troubleshooting by unit replacement is described according to the symptoms
indicated.
1. Key Unit. Note: Check key unit ribbon connection before replacement.
The following symptoms indicate a defective key unit. Replace the key unit.
a) When touching the keys, a certain key produces no signal at all.
b) When touching a number key, two figures or more are displayed.
c) When touching the keys, sometimes a key produces no signal.
a) When touching the keys, a certain key produces no signal at all.
b) When touching a number key, two figures or more are displayed.
c) When touching the keys, sometimes a key produces no signal.
2. Control Unit.
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Key unit test (Procedure M) to determine if control unit is faulty.
the Key unit test (Procedure M) to determine if control unit is faulty.
2-1 In connection with keys.
a) When touching the keys, a certain group of keys do not produce a signal.
b) When touching the keys, no keys produce a signal.
b) When touching the keys, no keys 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.
d) The corresponding segments of all digits do not light up; or they continue to light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
L
TOUCH CONTROL PANEL ASSEMBLY TEST
If the fuse is blown by incorrect door switching replace the defective switch(s) and the fuse.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE FUSE 10A WITH THE CORRECT VALUE REPLACEMENT
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the noise
filter. Using an ohmmeter, check between the termi-
nals as described in the following table.
Disconnect the leads from the terminals of the noise
filter. Using an ohmmeter, check between the termi-
nals as described in the following table.
MEASURING POINT
INDICATION OF
OHMMETER
OHMMETER
Between N and L
Approx. 680 k
Ω
Between terminal N and WHITE
Short circuit
Between terminal L and RED
Short circuit
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
J
NOISE FILTER TEST
NOISE FILTER
RESISTOR 10 M
Ω
1/2W
FUSE
N
L
LINE CROSS CAPACITOR
0.22
µ
/AC250V
NOISE SUPPRESSION COIL
WHT
RED
LINE BYPASS CAPACITOR
0.0033
0.0033
µ
/AC250V
LINE BYPASS CAPACITOR
0.0033
0.0033
µ
/AC250V
RESISTOR 680 K
Ω
1/2W
R-464(SL)
11
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
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.
b) Clock does not operate properly.
c) Cooking is not possible.
If the display fails to clear when the STOP/CLEAR key 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 key 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 key 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.
CARRY OUT 3D CHECKS.
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 key 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 key 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.
CARRY OUT 3D CHECKS.
M
KEY UNIT TEST
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
Remove the outer case and check voltage between the normal open terminal of the relay RY1 and
the normal open terminal of the relay RY2 on the power unit with an A.C. voltmeter. The meter should
indicate 230 - 240 volts, if not check oven circuit.
the normal open terminal of the relay RY2 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. 25.7V D.C.
Oven lamp / Turntable motor / Cooling fan motors
RY2
APPROX. 18.0V D.C.
High voltage transformer
CARRY OUT 4R CHECKS.
N
RELAY TEST
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.
O
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
(PWB) IS OPEN
G11
G10
G 9
G 8
G 7
G 6
G 5
G 4
G 3
G 2
G 1
STOP
CLEAR
Roast
Poultry
KITCHEN
TIMER
POWER
LEVEL
START
AUTO MINUTE
KG/LB
CONVERSION
Roast
Pork
Rice/Pasta
Vegetables
DOWN
UP
LESS
MORE
Chicken
Quarters
Chicken
Portions
Meat
Joint
Whole
Poultry
Minced
Meat
Ready
Meals
Roast
Beef/Lamb
Meal In One
Jacket
Potatoes
CLOCK
SET
10min.
10sec.
1min.
R-464(SL)
12
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
STEPS
OCCURRENCE
CAUSE OR CORRECTION
The rated AC voltage is not present between
1
the normal open terminal of the relay RY1 and
Check supply voltage and oven power cord.
the normal open terminal of the relay RY2.
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.
CN - A
a
d
c
b
(J1)
P
1
RY1
RY2
T1
VRS1
1
2
R-464(SL)
12
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
STEPS
OCCURRENCE
CAUSE OR CORRECTION
The rated AC voltage is not present between
1
the normal open terminal of the relay RY1 and
Check supply voltage and oven power cord.
the normal open terminal of the relay RY2.
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.
CN - A
a
d
c
b
(J1)
P
1
RY1
RY2
T1
VRS1
1
2
