LG 22LN4060 (CHASSIS:LM91P) Service Manual ▷ View online
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TROUBLE SHOOTING
1. NO POWER-Main PCBA
Is Adapter
Output VOLTAGE 19.4V
through of JK700?
NO POWER
Is 3.3V at C708?
Check waveform of X501
YES
NO
YES
NO
YES
check open or short at Line.
or change Adapter.
check the Lines of IC701,
If there is any problem at Line,
Change IC701
NO
Check Line short or open between
IC501 and X501,
Change IC501 or change X501
1
2
4
Is 1.8V at C745?
is 1.25V at C742?
3
YES
check the Lines of IC711,IC704
If there is any problem at Line,
Change IC704,IC711.
NO
Insert F/W
is 3.3V at 1pin of P120?
when push power key,
Is 0v at 2pin of P120?
Change control
Or check Line short or open of P120
5
is there any waver at 11pin of P120,
when use remote controller?
6
NO
YES
change IR board
Or check Line short or open of P120
NO
4
X501
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2. No raster (Power LED blue, black screen)
Is 19.4V at JK700?
NO RASTER
(Screen is not displayed)
Insert the F/W back
or REPLACE LCD MODULE
Is 1.8V at L501?
Is 1.25V at L500?
Is 1.25V at 4pin of IC704?
Is 1.8V at 2pin of IC711?
YES
NO
YES
NO
YES
Check Line short or open between
IC711/IC704 and IC501,
If there is any problem at Line,
Change IC711/IC704 or change IC501
NO
check open or short at Line and wafer
between IC704,IC711 and IC600.
If there is any problem at Line,
Change IC704,IC711 or IC501
1
2
is 3V at 3pin of IC801?
YES
It is not over 3V at 1pin of IC801.
Change Q802.
Or check Line short or open between
R803 and 95pin of IC501.
Change IC 501.
4
3
NO
check open or short at Line.
or change Adapter
is 12V at 1pin of P101?
If is not under 1.5V at R720,
change Q721 or check open and short
of Line among Q720 and Q721.
If is under 11V at L110,
Check open and short
Of line between L110 and P101.
6
NO
Put into LVDS cable completely?
LVDS cable have damage?
NO
If LVDS cable isn’t insulted enough,
Insult LVDS cable until locking hook.
If LVDS cable have damage,
Change LVDS cable
5
YES
YES
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3. Abnormal/No screen (All input)-Main PCBA
Put into LVDS cable completely?
LVDS cable have damage?
Abnormal/No screen
(all input)
Check waveform at signal
line of P101 (Clock:9,10
Data: 6,7,12,13,15,16,18,19)
YES
NO
YES
NO
YES
If LVDS cable isn’t insulted enough,
Insult LVDS cable until locking hook.
If LVDS cable have damage,
Change LVDS cable
1
Change module
WAVEFORMS
3
Is 12V at 1pin of P101?
If is not under 1.5V at R722,
change Q721 or check open and short
of Line among Q720 and Q721.
If is under 11V at L110,
Check open and short
Of line between L110 and P101.
2
3
NO
Check open and short
Of line between Q720 and P101.
Or Check LVDS cable have damage.
Another is change IC501.
6,7,12,13,15,16,18,19 Pin of 1201
(Data Line)
9,10Pin of P101
(Clock line)
- 13 -
Put into RF cable completely?
Abnormal screen (TV)
YES
NO
NO
insult RF cable tight and then
Cable nut screw tight.
1
Change Main PCBA
WAVEFORMS
Is 1.8V at 7pin of TU401?
2
Is I2C waveform
At 3,4pin of TU401?
3
4
Is IF waveform at 43,
44 pin of IC501?
NO
NO
3
3Pin of TU401 (SCL)
4Pin of TU401 (SDA)
4
43,44pin of IC501
If 1.7V is not at plus pin of TU401,
check It is over 3V at 2pin of IC401,
if it is not, Check Line between TU401
and IC401 is open or short.
Another is change IC401 or TU401
Check Line between TU401 and IC501
is open or short, Another is change
IC501 or TU401
Check Line between TU401 and IC501
is open or short, Another is change
IC501 or TU401
4. Abnormal screen (TV)-Main PCBA
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