No Raster - LG PT-43 Service Manual

8.NO RASTER

Is the voltage at
Pin 15,17 of IC501 3.3V?
Does the square
waveform from pin50
of IC501 appear?
No
Check/Replace
IC501
Is the waveform at
collector of Q402 normal?
No
Check/Replace
Q402, T401.
Is the waveform of collector
of Q403 normal?
No
Check/Replace
Q403.
Check/Replace
Check +B voltage
at Pin1 of P805A.
Normal
Check 5V, 9V,
Yes
12V lines
Check I
Yes
Bus lines
(SDA, SCL)
Yes
Yes
T401.
- 23 -
0V
Check F801.
No
OK
Check the voltage
of C812(+).
Yes
2 C
Check the voltage
at pin 4 of IC801.
6~ 8V
Check/Replace IC887, IC871.
Check the secondary voltage
are shorted
Open
Check/Replace
F801, D802,
IC801,IC802.
0V
Check/Replace
D802.
Lower than 6V
Check/Replace
D805,Q801,
ZD801.