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SCHEMATIC
NOTE: CONDITION OF OVEN
1. LIGHT UP DIAL OFF.
2. DOOR CLOSED.
THERMAL
CUT-OUT
MONITOR
125˚C (OVEN)
FUSE 20A
A5
AC120V
60 Hz
A3
DOOR SENSING
SWITCH
SECONDARY
INTERLOCK SWITCH
PROCEDURE
LETTER
I
CONTROL PANEL ASSEMBLY TEST
WARNING : To prevent an electric shock do not touch the electrical parts and the printed wiring
The 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 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.
6) After that procedure, re-connect the power supply cord.
1. Control Panel
The following symptoms indicate a defective control unit.
1-1 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.
NOTE:
THERMAL
CUT-OUT
145˚C (MAG.)
CONTROL UNIT
A1
OL
FM
OVEN
FAN
LAMP
MOTOR
Figure O-1 Oven Schematic-OFF Condition
TEST PROCEDURES
board. Because the control unit is "TRANSLESS CIRCUIT" and many electrical parts
are used at A.C. line voltage.
Indicates components with potential above 250 V.
POWER
TRANSFORMER
AM
ANTENNA
MOTOR
COMPONENT TEST
5
R-21JCA
CAPACITOR
0.94 µF
2400V
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