15
Fig.5-1
glass tray
B
B
R
R
E
E
A
A
K
K
D
D
O
O
W
W
N
N
A
A
N
N
A
A
L
L
Y
Y
S
S
I
I
S
S
A
A
N
N
D
D
T
T
H
H
E
E
M
M
E
E
A
A
N
N
S
S
O
O
F
F
O
O
V
V
E
E
R
R
H
H
A
A
U
U
L
L
I
I
N
N
G
G
Before overhauling a microwave oven, you should judge the breakdown and the cause correctly, then you can
repair it with corresponding ways. The overhauling must be proceed in order, any hasty conclusion is not
recommendable, otherwise over-working would be done when repair. The microwave oven may occur compound
breakdown due to all kinds of different reasons, thus, when overhaul, they all should be taken into consideration.
Special attention must be given to the microwave leakage and the electric insulation when examine because they
may do harmful to the repairing staff.
1
1
.
.
1
1
6
6
E
E
X
X
A
A
M
M
I
I
N
N
I
I
N
N
G
G
T
T
H
H
E
E
B
B
R
R
E
E
A
A
K
K
D
D
O
O
W
W
N
N
C
C
A
A
U
U
S
S
E
E
S
S
.
.
How to examine a microwave oven with breakdown? A better means which demonstrated in practical operating
are through inspecting and listening. On the basis of large amounts of perceptual knowledge, you can judge and
analyze the break down quickly and correctly.
1
1
.
.
1
1
6
6
.
.
1
1
I
I
N
N
S
S
P
P
E
E
C
C
T
T
I
I
O
O
N
N
.
.
Inspect whether the oven shape is disordered and where is the disordered position, If any. It is normal if the
cabinet disordered a little, but abnormal if the oven, the door disordered, the door hook broken, the door crooked,
or there are too much looseness between the door and the oven after the door is closed .
1
1
.
.
1
1
6
6
.
.
2
2
L
L
I
I
S
S
T
T
E
E
N
N
I
I
N
N
G
G
.
.
Listening to the sound of the oven operating and the noise of the fan. Minor “wen wen” noise, cycling“kala”noise
and “shishi” noise should be considered as normal. But it is abnormal if the following noises occur:
(1) Sound “wen wen ” noise.
(2) Long time “shishi” noise.
(3) Strike sound like “Pipa pipa”
1
1
.
.
1
1
7
7
S
S
P
P
O
O
T
T
E
E
X
X
A
A
M
M
I
I
N
N
I
I
N
N
G
G
S
S
T
T
E
E
P
P
S
S
O
O
F
F
T
T
H
H
E
E
M
M
I
I
C
C
R
R
O
O
W
W
A
A
V
V
E
E
O
O
V
V
E
E
N
N
1
1
.
.
1
1
7
7
.
.
1
1
E
E
X
X
A
A
M
M
I
I
N
N
E
E
T
T
H
H
E
E
M
M
I
I
C
C
R
R
O
O
W
W
A
A
V
V
E
E
I
I
N
N
S
S
U
U
L
L
A
A
T
T
I
I
N
N
G
G
R
R
E
E
S
S
I
I
S
S
T
T
A
A
N
N
C
C
E
E
Measure the insulating resistance with a multimeter or a
megaohmmeter the value should not be less than 2 megaohms.
Otherwise, part examination should be taken at once. Such as
checking whether the motor, the thermal cutout, the transformer or
the capacitor are electricity leaking.
1
1
.
.
1
1
7
7
.
.
2
2
E
E
X
X
A
A
M
M
I
I
N
N
A
A
T
T
I
I
O
O
N
N
O
O
F
F
T
T
H
H
E
E
R
R
E
E
S
S
I
I
S
S
T
T
A
A
N
N
C
C
E
E
V
V
A
A
L
L
U
U
E
E
O
O
F
F
T
T
H
H
E
E
M
M
I
I
C
C
R
R
O
O
W
W
A
A
V
V
E
E
O
O
V
V
E
E
N
N
Close the door, set the time (the oven is at operating condition but
the power plug haven’t been plugged in ), measure the two feet (L -
N) of the power plug with R×1 grade of an multimeter, the resistance
value should be about 2.5 ohm. If open circuit occurs, then you must
check whether the 8A fuse is broken
、
the primary winding of the transformer is open circuit
、
the thermal cutout is
open circuit or not, you must check whether the interlock device is put through or all the plugs are connected well.
If short circuit occurred or the resistance less than 1.5 ohms, you
should check whether the primary winding of the power transformer
is short – circuited or part short – circuited.
1
1
.
.
1
1
7
7
.
.
3
3
E
E
X
X
A
A
M
M
I
I
N
N
A
A
T
T
I
I
O
O
N
N
O
O
F
F
M
M
I
I
C
C
R
R
O
O
W
W
A
A
V
V
E
E
L
L
E
E
A
A
K
K
A
A
G
G
E
E
Measure the microwave leakage with a microwave leakage measure.
Place a graduate of 275ml water at the middle of the glass tray of the
oven (FIG.5 - 1). Close the door, power set high, time set to 3
minutes, press the starting button to operate the oven. After rectified
the microwave leakage measure, measure around the door crack,
those hole position of the window and the air vent at four sides of the
oven with the probe of the measure. When measure, the moving
