Samsung SC-148B Service Manual page 21

No SLED operation
Move pick-up out.
Insert 2 FPC and power cord.
Pick-up moves in?
N
The below waveform is outputted in
IC301 22Pin, 23pin ?
Y
The below signal is inputted
in CN503 A,A, B,B termial?
Y
The opposition signal is inputted
in CN503 A, A, B, B termial?
Y
Replace SLED Motor.
Y
SLED runs normally.
N
Refer to 'Check power source and initial state'
N
Voltage of IC501 4pin - 12V,
5pin - 5V?
N
22
Y
Check R506, R507,
R512 soldering.
After checking IC501
N
soldering, no error, replace
IC