Read Sharp R-951M Service Manual online
R-951M - 8
TOUCH CONTROL
CONT
...
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 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.
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
OCCURANCE
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)
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
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.
visual inspection of the varistor for burning
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.
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 control
unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
unit with an A.C. voltmeter.
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, convection cooking
operation or grill operation.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, convection cooking
operation or grill operation.
DC. voltage indicated ........... Defective relay.
DC. voltage not indicated ..... Check diode which is connected to the relay coil. If diode is good, control unit
is defective.
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. 18.0V D.C.
Convection heating element
RY4
Approx. 18.0V D.C.
Grill heating element
RY5
Approx. 24.0V D.C.
Fan motor
RY6
Approx. 24.0V D.C.
Convection fan motor
RY7
Approx. 24.0V D.C.
Damper motor
CARRY OUT 4R CHECKS.
CN - E
CN - D
D25
a
b
c
d
VRS1
CN - A
RY6
(J1)
1
3
5
31
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