R239(W)
7 – 1
R239(W)
Service Manual
CHAPTER 7.
TROUBLESHOOTING GUIDE
[1] FOREWORD
When troubleshooting the microwave oven, it is helpful to follow the
Sequence of Operation in performing the checks. Many of the possible
causes of trouble will require that a specific test be performed. These
tests are given a procedure letter which will be found in the "Test Pro-
cedure"section.
IMPORTANT:
If the oven becomes inoperative because of a blown fuse F1 T6.3A in
the 1st. latch switch SW1 - relay RY1 - 2nd. interlock relay RY2 - mon-
itor switch SW2 circuit, check the 1st. latch switch SW1, relay RY1,
2nd. interlock relay RY2 and monitor switch SW2 before replacing the
fuse F1 T6.3A.
[2] CHART
MAGNETRON
(MG)
HIGH
VOLTAGE
T
RANSFORMER
(T)
H.V.
RECTIFIER
ASSEMBLY
HIGH
VOLTAGE
WIRE
HIGH
VOLTAGE
C
APACITOR
(C)
1ST.
LATCH
S
WITCH
(SW1)
2ND.
INTERLOCK
R
ELAY
CONTROL
SWITCH
(SW3)
MONITOR
SWITCH
SW2)
TEMPERATURE
F
USE
(TF)
150
C
(OVEN)
FAN
M
OTOR
(FM)
TURNTABLE
M
OTOR
(TTM)
FUSE
(F1)
T6.3A
TOUCH
C
ONTROL
PANEL
RELAY
(RY-1)
RELAY
(RY-2)
FOIL
PATERN
O
N
P
.W.B.
POWER
S
UPPLY
C
ORD
SHORTED
W
IRE
H
ARNESS
OPENED
WIRE
HARNESS
OVEN
LAMP
(OL)
WALL
OUTLET
MISADJUSTMENT
S
WITCH
HOME
FUSE
OR
BREAKER
BLOCKED
COOLING
F
AN
BLOCKED
VENTILATION
NOISE
F
ILTER
SWITCH
U
NIT
H.V.
FUSE
(F2)
OFF
CONDITION
PROBLEM
CONDITION
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE
ON
CONDITION
A B C
CK
D
E
E
E F G G H K
M N
I L J
M
RE CK CK RE CK CK CK CK CK
Home fuse blows when pow-
ersupply cord is plugged into
wall outlet.
FUSE (F) T6.3A blows when
power supply cord is plug-
ged into wall outlet.
"88:88" does not appear in
display but power supply cord
is plugged into wall outlet.
Display
does
not
operate
properly when STOP button
is pressed.
Oven does not start when the
START button is touched.
(Display appears)
Oven lamp does not light
(Display appears.)
Fan motor does not operate.
(Display appears.)
Turntable motor does not
operate. (Display appears.)
Oven or any electrical parts
does not stop when cooking
time is 0 or STOP button is
pressed.
Oven seems to be operating
but little or no heat is pro-
duced in oven load. (Micro-
wave power level is set at
100%)
Oven does not seems to be
operating
properly
when
70%,50%, 30% or 10% is
set. (Oven operates properly
at 100%.)
Oven goes into cook cycle
bu tshuts down before end
of cooking cycle.
