R21LCF
8 – 4
3. Discharge high voltage capacitor.
4. If the monitor 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 monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH,
DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with "monitor fuse and monitor
switch assembly" part number FFS-BA033WRKZ, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is
comprised of a 20 ampere fuse and switch.
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.
[10] Procedure I: NOISE FILTER TEST
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. Disconnect the lead wires from the terminal the noise filter. Using an ohmmeter,
check between the terminals as described in the following table. If incorrect reading
are obtained, replace the noise filter.
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.
[11] Procedure J: CONTROL PANEL ASSEMBLY TEST
WARNING: To prevent an electric shock do not touch the electrical parts and the printed wiring board. Because the control unit is “TRANSLESS CIR-
CUIT” and many electrical parts are used at A.C. line voltage.
The control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper main-
tenance cannot be performed with only a voltmeter and ohmmeter. In this service manual troubleshooting by unit replacement is described according
to the symptoms indicated.
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) Disconnect the leads to the primary of the power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
6) After that procedure, re-connect the power supply cord.
1. Control Unit.
The following symptoms indicate a defective control unit.
1) In connection with LEDs
a) At a certain LED, all or some LEDs do not light up.
b) At a certain LED, brightness is low.
c) Only one LED does not light up.
d) All or some LEDs continue to light up.
e) A certain group of LEDs do not light up.
f) The LEDs flicker.
2) Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Cooking is not possible.
c) Cooking time can not be set.
MEASURING POINT
INDICATION OF OHMMETER
Between N and L
Open circuit.
Between terminal N and WHITE
Short circuit.
Between terminal L and RED
Short circuit.
FUSE
LINE CROSS CAPACITOR 0.22μF AC250V
WHITE
RED
NOISE SUPPRESSION COIL
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V
20A
NOISE
FILTER
N
L
