LG 42SL90-UA (CHASSIS:LA92S) Service Manual ▷ View online
LA92S Trouble shooting guide – RGB PC
Check JK106
Can you see the normal waveform?
Can you see the normal waveform?
YES
JK106 may have problem. Replace this Jack.
NO
Check the input (Pin K1,K2,K3,L1,L3)
of LGE3369(IC601).
Measure waveform at R644,R645,C615,C610 and C616
because it’s more easy to check.
Can you see the normal waveform?
of LGE3369(IC601).
Measure waveform at R644,R645,C615,C610 and C616
because it’s more easy to check.
Can you see the normal waveform?
Video
NO
YES
YES
Check all power domain of LGE7329 (IC801)
(3.3V, 1.9V_CORE,1.26V)
(3.3V, 1.9V_CORE,1.26V)
& crystal output (X800 / 12MHz)&FRC_RESET
Measure Power & waveform at L800,L801,L802,L803,
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
This board has big problem because FRC chip(LGE7329) have some troubles.
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
Main chip(LGE3369)
This board has big problem because Main chip(LGE3369) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3369 or no
After checking thoroughly all path once again, You should decide to replace LGE3369 or no
LA92S Trouble shooting guide – HDMI
Check input connect
JK200,JK201,JK202,JK203
Can you see the normal waveform?
JK200,JK201,JK202,JK203
Can you see the normal waveform?
Check DDC communication lines
(IC200)
(IC200)
JK200,JK201,JK202,JK203
may have problem. Replace this Jack.
Check the output of TDA9996HL(IC602)
_HDMI1,2,3
_HDMI1,2,3
or HDMI4.
.
Can you see the normal waveform?
After checking the Power of this chip, you should decide to replace this or not.
Check HDCP communication lines(IC105)
After checking the Power of this chip, you should decide to replace this or not.
YES
YES
YES
NO
NO
NO
Video
NO
YES
YES
Check all power domain of LGE7329 (IC801)
(3.3V, 1.9V_CORE,1.26V)
(3.3V, 1.9V_CORE,1.26V)
& crystal output (X800 / 12MHz)&FRC_RESET
Measure Power & waveform at L800,L801,L802,L803,
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
L804,L806
because it’s more easy to check.
Can you see the normal waveform?
This board has big problem because FRC chip(LGE7329) have some troubles.
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
After checking thoroughly all path once again, You should decide to replace
LGE7329.
Although you replace it, you cannot see normal display, decide to replace
Main chip(LGE3369)
This board has big problem because Main chip(LGE3369) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3369 or not
After checking thoroughly all path once again, You should decide to replace LGE3369 or not
LA92S FHD-120 Model
Audio Trouble Shooting Guide
LA92S FHD
LA92S FHD
-
-
120 Model
120 Model
Audio Trouble Shooting Guide
Audio Trouble Shooting Guide
LA92S AUDIO PATH
D-sub RGB
HDMI 1
Digital Audio (Optic)
Digital AMP
NTP3100L
RS-232C (Ctrl./SVC)
I2S
RGB/H/V
Half-NIM T
uner
MAX3232
Saturn6
Saturn6
(ATSC US)
(ATSC US)
LGE3369A
LGE3369A
MPEG2
Linux
Scaler
IF +/-
SIF
TU_CVBS
Reset / IF_AGC …
SDA/SCL_5V
HDMI4
Audio L/R
Audio L/R (for RGB)
HDMI 2
SPDIF
RX/TX
RX/TX
JACK PACK
JACK PACK
at REAR
at REAR
JACK PACK
JACK PACK
at SIDE
at SIDE
TR Buffer
VSB/QAM
Demod.
LGDT3305
TS In[0…7]
TS_clk, SOP, Val
EEPROM
AV
Component 1
Y Pb Pr, L/R
CVBS, Y/C, L/R
Component 2
Y Pb Pr, L/R
USB2.0
SCL, SDA_3.3V
DP/D
M
M
O.C. Protector
+5V
+5V
HDMI 3
HDMI S/W
TDA9996
X-tal
25MHz
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