Trouble Shooting - LG PF-43A10 Service Manual

1. NO RASTER
No
Check/Replace
IC501
No
Check/Replace
Q421, T421, R421
No
Check/Replace
Q422
2. NO RASTER (SOUND OK)
Abnormal
Check/Replace
T422

TROUBLE SHOOTING

Check+B voltage at C892
Normal
Is the voltage at Pin5
of IC501 9.1V?
Check the voltage
Yes
Does the square
waveform from pin6 of
IC501 appear?
Yes
Is the waveform of
collector of Q421 normal?
Yes
Is the waveform of
collector of Q422 normal?
Yes
Check/Replace
T422
Normal
Check the voltage of
HV, SCREEN of CPT
Normal
Check/Replace
CRT Boards
0V
Check F801A
No
5V, 9V, 12V line
Check the voltage
No
of C808, C809
Check I 2 C Bus
lines (SDA, SCL)
Check the voltage
of pin9 of IC801, IC821
Check/Replace
IC802, IC822
Check the secondary
voltage are shorted
Check the voltage of
CRT Heater
Abnormal
Check the Heater
pulse of pin9 of T402
Normal
Check/Replace
Connector, FR469, FR470
- 33 -
Open
Check/Replace
F801A, D821,
OK
D809~812, IC801,
IC821
0V
Check/Replace
150~380V
D821, D809~812
Lower than 6V
Check/Replace
D801, D804, D805,
D824, D830, Q801,
6~8V
Q821, IC801, IC821
Abnormal
Check/Replace
T422