LG PT-43, Service Manual

Page: 23 / 69

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Check +B voltage
at Pin1 of P805A.
Is the voltage at
Pin 15,17 of IC501 3.3V?
Does the square
waveform from pin50
of IC501 appear?
Is the waveform at
collector of Q402 normal?
Is the waveform of collector
of Q403 normal?
Check/Replace
T401.
Check/Replace
F801, D802,
IC801,IC802.
Check/Replace
D802.
Check/Replace
D805,Q801,
ZD801.
Check/Replace
IC501
Check/Replace
Q402, T401.
Check/Replace
Q403.
Check 5V, 9V,
12V lines
Check I 2 C
Bus lines
(SDA, SCL)
Check F801.
Check the voltage
of C812(+).
Check the voltage
at pin 4 of IC801.
Check/Replace IC887, IC871.
Check the secondary voltage
are shorted
Normal 0V
OK
6
~
8V
Open
0V
Lower than 6V
No
No
No
No
Yes
Yes
Yes
Yes
Yes
8.NO RASTER