LG PF-43A20, Service Manual

Page: 24 / 59

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NO RASTER
Check +B voltage
at R406.
Is the voltage at
Pin 3 of IC501 9V?
Does the square
waveform from pin 4 of
IC501 appear?
Is the waveform at
collector of Q401 normal?
Is the waveform of collector
of Q402 normal?
Check/Replace
T401
Check/Replace
F801A, D821, IC825
Check/Replace
D821
Check/Replace
D801, D802,
D807, ZD801,
Q801, IC825
Check/Replace
IC501
Check/Replace
Q401, T401,
R416, R417
Check/Replace
Q402
Check 5V, 9V,
12V lines
Check I 2 C
Bus lines
(SDA, SCL)
Check F801A
Check the voltage
of C809(+)
Check the voltage
at pin 9 of IC825
Check/Replace IC887,
D825, D826 Check the
secondary voltage are
shorted
Normal 0V
OK
200
~
380V
6
~
8V
Open
0V
Lower than 6V
No
No
No
No
Yes
Yes
Yes
Yes
Yes