Sharp R-380A Service Manual page 16

R-380A
PROCEDURE
LETTER
M RELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin No 3 of the 2-pin connector (A) and the
common 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 or
convection cooking operation.
DC. voltage indicated ............... Defective relay.
DC. voltage not indicated ......... Check diode which is connected to the relay coil. If diode is good,
RELAY SYMBOL
CARRY OUT 4R CHECKS.
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.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
1
2
3
4
NOTE: *At the time of making these repairs,
make a visual inspection of the varistor.
Check for burned damage and examine
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.
O AH SENSOR TEST
Checking the initial sensor cooking condition
(1) The oven should be plugged in at least two minutes before sensor cooking.
(2) Room temperature should not exceed 35˚C.
(3) The unit should not be installed in any area where heat and steam are generated. The unit should
not be installed, for example, next to a conventional surface unit. Refer to the "INSTALLATION
Instructions" .
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To
TEST PROCEDURES
control unit is defective.
OPERATIONAL VOLTAGE
RY1 APPROX. 24.5V D.C.
RY2 APPROX. 24.0V D.C.
OCCURRENCE
The rated AC voltage is not present between
Pin No. 3 of the 2-pin connector (A) and the
common terminal of the relay RY2.
The rated AC voltage is present to primary
side of low voltage transformer.
Only pattern at "a" is broken.
Pattern at "a" and "b" are broken.
COMPONENT TEST
CONNECTED COMPONENTS
Oven lamp / Turntable motor / Cooling fan motor
Power transformer
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and repair.
*Insert jumper wire J1 and solder.
*Insert the coil RCILF2003YAZZ between "c" and "d".
c
(J1)
14
a
d
b