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Troubleshooting & Technical Data
PROCEDURE
LETTER
M
FOIL PATTERN ON THE PRINTED WIRING BOARD TEST
NOTE: To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on
the PWB, this foil pattern acts as a fuse.
1.
Foil pattern check and repairs.
a. Disconnect power supply cord and remove outer cabinet case.
b. Open door and block it open.
c. Discharge high-voltage capacitor.
d. Follow steps on troubleshooting table below for repair.
e. Make a visual inspection of the varistor. Check for
burned damage and examine the transformer with
a tester for the presence of layer short-circuit
(check the primary coil resistance which is approx-
imately 210 ohm ± 15%). If any abnormal condi-
tion is detected, replace the PWB.
f. Reconnect all leads removed from components
during testing.
g. Reinstall the outer cabinet case, then reconnect
power supply cord.
h. Run the oven and check all functions.
2.
Follow the troubleshooting guide given below, if indicator does not light up after above check and repairs are
finished.
a. Disconnect power supply cord and remove outer cabinet case.
b. Open door and block it open.
c. Discharge high-voltage capacitor.
d. Disconnect the leads to the primary of the power transformer and ensure that these leads remain isolat-
ed from other components and oven chassis by using insulation tape.
e. After that procedure, re-connect the power supply cord.
f. Follow steps on troubleshooting table below for repair.
STEPS
g. Disconnect power supply cord and remove outer cabinet case.
h. Open door and block it open.
i.
Discharge high-voltage capacitor.
j.
Reconnect all leads removed from components during testing.
k. Reinstall the outer cabinet case, then reconnect power supply cord.
l.
Run the oven and check all functions.
P P
r r
i i
o o
r r
t t
o o
S S
P P
r r
i i
o o
r r
t t
o o
S S
TEST PROCEDURES
STEPS
OCCURRENCE
1
Only pattern at "a" is broken.
2
Pattern at "a" and "b" are broken.
OCCURRENCE
The rated AC voltage is not present between
1
Pin No. 1 of the 2-pin connector (A) and the
common terminal of the relay RY1.
The rated AC voltage is present at primary
2
side of low voltage transformer.
e e
r r
i i
a a
l l
N N
u u
m m
b b
e e
r r
1 1
2 2
0 0
0 0
e e
r r
i i
a a
l l
N N
u u
m m
b b
e e
r r
1 1
2 2
0 0
0 0
MICROWAVE OVEN
COMPONENT TEST
Replace PWB
Replace PWB
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and repair.
6-10
1 1
5 5
4 4
1 1
5 5
4 4
CAUSE OR CORRECTION
CN - A
d
(J1)
b
c
a
CAUSE OR CORRECTION
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