LG 22LN4000, Service Manual

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Only for training and service purposes
4. Abnormal screen (TV)-Main PCBA
wœ›G•›–GymG Šˆ‰“ŒGŠ–”—“Œ›Œ“ f
Abnormal screen (TV)
YES
NO
NO
insult RF cable tight and then
Cable nut screw tight.
1
Change Main PCBA
WAVEFORMS
pšG\}Gˆ›G\—•G–G {|[WXf
2
pšGpYjG žˆŒ–™”G
h›G]S^—•G –G {|[WXf
3
4
pšGpmG žˆŒ–™”G ˆ›G]^
S]_G—•G–G pj]WWf
NO
NO
3
^w•G–G {|[WXG OzjsP
]w•G–G {|[WXG OzkhP
4
]^SG]_—•G –G pj]WW
If 4.9V is not at plus pin of L705, check
It is over 3V at 2pin of IC706,
if it is not, Check Line between IC706
and IC600 is open or short.
Another is change IC706
Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401
Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401