R-209(IN)
R-209(W)
R-209(Y)
14
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
L
CONTROL UNIT TEST
CAUTION: DO NOT TOUCH THE ELECTRICAL PARTS AND THE PRINTED WIRING BOARD TO
PREVENT AN ELECTRIC SHOCK. BECAUSE THE CONTROL UNIT IS “ TRANSLESS
CIRCUIT ” AND ALL ELECTRICAL PARTS ARE USED AT A.C. LINE VOLTAGE.
The control unit consists of circuits including semiconductors such as LSI, etc. Therefore, unlike
conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter. In this service manual, troubleshooting by unit replacement is described according to the
symptoms indicated.
Control unit.
The following symptoms indicate a defective control unit.
a) When rotating the potentiometer, the power level can not be selected.
b) Cooking is not possible.
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 RY1 on the control unit with an A.C. voltmeter.
The meter should indicate 230 volts, if not check oven circuit.
Relay Test
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,
control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
Approx. 12.0V D.C.
Oven lamp / Turntable motor / Fan motor
RY2
Approx. 11.0V D.C.
High voltage transformer
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 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.
CARRY OUT 3D CHECKS.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
The rated voltage is not applied between Pin
Check supply voltage and oven power cord.
No. 3 of the 2 pin connector (A) and the
common terminal of the relay RY1.
2
Only pattern at “a” is broken.
*Insert jumper wire J1 and solder.
3
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. If any abnor-
mal condition is detected, replace the
defective parts.
CARRY OUT 4R CHECKS.
M
RELAY TEST
D71
R75
(F1)
(J2)
D1
(J1)
a
b
c
d
D70
