TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER
COMPONENT TEST
H
BLOWN FUSE
If the fuse in the upper latch switch and monitor switch (Australia) circuit is blown when the door
is opened, check the upper latch switch and monitor switch before replacing the blown fuse (Refer
to Test Procedure E and
G).
In case the fuse is blown by an improper switch operation, replace the
defective switch and fuse at the same time.
Replace just the fuse if the switches operate normally.
CAUTION: REPLACE BLOWN FUSE 10 AMPERE FUSE,
PART NO.
QFS-CQOOlYBEO
I
MAGNETRON THERM0 CUT-OUT TEST
A continuity check across the therm0 cut-out terminals should indicate a closed circuit unless the
temperature of the therm0 cut-out reaches approximately 104°C. The therm0 cut-out resets auto-
matically at approximately 79°C.
An open therm0 cut-out indicates overheating of the magnetron assembly. Check for restricted air
flow to the magnetron through the opening in the chassis, especially the cooling duct.
J
COOK RELAY OR HEATER RELAY TEST
Disconnect the wire leads from relay coil terminals. A continuity check of the cook relay coil
should indicate approximately 160 ohms.
Supply the 12 volts D.C. to the relay coil terminals, and then check if there is a continuity between
the contacts of relay.
K
STOP SWITCH TEST
Isolate the stop switch and connect the ohmmeter leads to the common
(COM)
and normally open
(NO) terminals of the switch. The meter should indicate an open circuit with the open button
pushed and a closed circuit with the open button released. In case improper operation is indicated,
replace the stop switch.
L
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI,
ICs,
etc. There-
fore, unlike the convectional microwave ovens, proper maintenance cannot be performed with only
a voltmeter and ohmmeter. For test procedure or troubleshooting guide, refer to the CHAPTER V
“TOUCH CONTROL PANEL ASSEMBLY”.
57
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