R403KKT
8 – 4
3. Discharge high voltage capacitor.
4. If the monitor fuse is blown when the door is opened, check the primary interlock switch, secondary interlock relay (RY2), relay (RY1) 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 SWITCH, SECONDARY INTERLOCK RELAY,
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 or FFS-BA037WRKZ, even if the monitor switch operates normally. The monitor fuse and moni-
tor 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 readings 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: TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper
maintenance cannot be performed with only a voltmeter and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key Unit, and also the Control Unit is divided into
two units, CPU Unit and Power Unit, and troubleshooting by unit replacement is described according to the symptoms indicated.
Before testing,
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.
1. Key Unit
NOTE:
1) Re-install the outer case (cabinet).
2) Reconnect the power supply cord after the outer case is installed.
3) Run the oven and check all functions.
The following symptoms indicate a defective key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
2. Control Unit.
The following symptoms indicate a defective control unit.
1) In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
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 20A
NOISE FILTER
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR
0.22μF / AC 250V
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V
L
RED
WHITE
N
