19
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate conti-
nuity for a short time and should indicate approximately 10 M
Ω
once the capacitor is charged. If the
above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either of
the terminals and case. If it is shorted, replace the capacitor.
E
PRIMARY INTERLOCK SWITCH AND THIRD DOOR SWITCH TEST
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicated an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the switch.
F
SECONDARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicated an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the door sensing switch.
SECONDARY INTERLOCK RELAY
Disconnect two (2) wire leads from the tab terminal of the secondary interlock relay (RY2). Check the
state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay contacts
are closed, replace the circuit board entirely or the relay itself.
G
MONITOR SWITCH
Disconnect the oven from power supply.
Before performing this test, make sure that the primary interlock switch and the secondary interlock
relay are operating properly, according to the above Test Procedures. Disconnect the wire lead from the
monitor switch (NC) terminal. Check the monitor switch operation by using the ohmmeter as follows.
When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator
is pushed by a screw driver through the lower latch hole on the front plate of the oven cavity with the
door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indi-
cate an open circuit. If improper operation is indicated, the switch may be defective. After testing the
monitor switch, re-connect the wire lead to the monitor switch (NC) terminal and check for continuity
of monitor circuit.
H
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
SCREW DRIVER
MONITOR SWITCH
OHMMETER
PRIMARY
INTERLOCK
SWITCH
COM.
N.C.
C/T FUSE TEST
A continuity check across the C/T fuse terminals should indicate a closed circuit unless the temperature
of the C/T fuse reaches approximately 266
O
F(130
O
C). An open C/T fuse indicates overheating of the
magnetron. Check for restricted air flow to the magnetron, especially the cooling fan air guide.
CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM
TEMPERATURE, REPLACE TEMPERATURE FUSE.
If the C/T fuse is blown when the door is opened, check the secondary interlock relay, primary interlock
switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing
the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE SECONDARY INTERLOCK RELAY,
PRIMARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH
FOR PROPER OPERATION.
If the C/T fuse is blown by improper switch operation, the C/T fuse and monitor switch must be replaced
with "C/T fuse and monitor switch assembly" part number FFS-BA019/KIT, even if the monitor switch
operates normally. The C/T fuse and monitor switch assembly is comprised of a 20 ampere fuse and
switch.
Summary of Contents for VMOC206SS
Page 3: ...3 Notes...
