17
R-25AM
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
RY1, RY3 and RY4 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.
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. 25.9V D.C.
Oven lamp, Blower motor and Antenna motors
RY3
APPROX. 25.0V D.C.
High voltage transformer (MG1)
RY4
APPROX. 25.0V D.C.
High voltage transformer (MG2)
CARRY OUT 4R CHECKS.
To protect the electronic circuits, this model is provided with a fine fuse added to the primary on the
PWB. If the fuse 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 at
Check supply voltage and oven power cord.
POWER terminal of CPU connector (CN-A).
2
The rated AC voltage is present at primary
Touch control transformer or secondary circuit defective.
side of touch control transformer.
Check and repair.
3
Fuse on the PWB is open.
Replace the fuse with new one.
(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.
CARRY OUT 4R CHECKS.
P
PROCEDURES TO BE TAKEN WHEN THE FUSE ON THE PRINTED WIRING BOARD(PWB) IS
OPEN
