Samsung AW078AA - Symptom-Based Troubleshooting

5-2 Samsung Electronics
5-2 Troubleshooting by Symptom
5-2-1 No power
1) Check points
(1) Is the voltage of the power source normal ? (the rating voltage ±10% range.)
(2) Is the electric wire in good contact ?(CN 71, RY 71)
(3) Is the output voltage of the IC01(KA 7812) normal ?(DC 11.5V ~ DC 12.5V)
(4) Is the output voltage of the IC02(KA 7805) normal ?(DC 4.5V ~ DC 5.5V)
Turn off the power, and then turn it on again five
seconds later.
Replace the assembly main PCB.
Dose the buzzer sound, when the power on?
Check whether the "COOLING ICON" LED lamp is on,
and the operation starts when pressing the ON/OFF
button of the remocon.
Is the primary voltage of the transformer normal?
(the rating voltage ±10% range.)
Is the secondary voltage of the transformer normal?
(AC 13V ~ AC 17V)
Is the F701(3.15A) fuse blown?
Is the rectifier diode(D101~D104) normal?
Are the IC01(KA7812) and IC02(KA7805) normal?
- Is the voltage of DC 17V ~ DC 23V applied at both
ends of the C101 electrolytic condenser?
- Is the voltage of DC 12V applied at both ends of
the C102 electrolytic condenser?
- Is the voltage of DC 5V applied at both ends of
the C103 electrolytic condenser?
Normal operation.
Normal operation.
Replace the fuse.
Check the power cord and electric wire.
Check and replace the trans.
• Check the D101 ~ D104 for cold soldering.
• Replace the rectifier diode
• Check both ends of the C101 for short
and cold soldering.
• Check the +12V for a short.
• Check the +5V for a short.
• Check and replace the C101~104.
• Check the IC01, and IC02 for cold
soldering and a short.
• Replace the IC01, and IC02.
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
N
N
N
N
N
DB98-04511A(1)-2 3/20/02 2:25 PM Page 5-2