16
R-55TS
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
in), the meter should indicate an open circuit. If improper operation is indicated, the switch may be
defective. After testing the monitor switch, reconnect the wire lead to the monitor switch (COM)
terminal and check the continuity of
the monitor circuit.
5. Reconnect all leads removed from
components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after
the outer case is installed.
8. Run the oven and check all functions.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the C/T fuse is blown when the door is opened, check the primary interlock relay, secondary interlock
switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing the
blown C/T fuse.
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE PRIMARY INTERLOCK RELAY,
SECONDARY 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-BA036WRKZ, even if the monitor switch operates
normally. The C/T fuse and monitor switch assembly is comprised of a 15 ampere fuse and switch.
A continuity check across the C/T fuse terminals should indicate a closed circuit unless the temperature of the
C/T fuse reaches approximately 302˚F(150˚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 C/T FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE
THE C/T FUSE.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
H
BLOWN C/T FUSE TEST
Monitor
Switch
Secondary
Interlock Switch
Screw Driver
Ohmmeter
BLU/WHT
RED
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Make sure the heater is cooled completely.
5. Resistance of heater.
Disconnect the wire leads to the heater to be tested. Using ohmmeter with low resistance range.
Check the resistance across the terminals of the heater as described in the following table.
Table: Resistance of heater
Parts name
Resistance
Upper heater
Approximately 18.9
Ω
Lower heater
Approximately 28.2
Ω
6. Insulation resistance.
Disconnect the wire leads to the heater to be tested. Check the insulation resistance between the
heater terminal and cavity using a 500V - 100M
Ω
insulation tester. The insulation resistance should
be more than 10 M
Ω
in the cold start.
I
UPPER HEATER AND LOWER HEATER TEST
