LG 42LH90 (CHASSIS:LA92C) Service Manual ▷ View online
POWER Block (3.3V)
POWER Block (3.3V)
+3.3V
IC600
NTP-3100L
IC101
MX25L3205
L110
Serial Flash Memory
IC701
SC4215I
L702
+1.8V for Saturn5 DDR
+3.3V_VDDP
L2300
L2301
L2301
IC2301
NTP-3100L
IC102
NAND Flash
Memory
Memory
EEPROM
IC3503
AZ1085S-ADJ
L3502
Dimming_PLL_1.8V
L3501
Dimming_RX_1.8V
Dimming_1.8V
IC104
AT24C512
+3.3V_HDMI
L501
IC502
TDA9996HL
+3.3V_BCM3548
L103
+1.8V_AMP
IC703
AP1117E18G
L721
IC704
MP2212DN
L720
L605
L104
L101
+1.8V_DDR
Check JK1202, JK1206
Can you see the normal waveform?
Can you see the normal waveform?
NO
JK1202,JK1206 may have problem. Replace this Jack.
Check the input (Pin AN17,AM19) of LGE3159(IC100).
Measure waveform at C112,C118 because it’s more easy to check.
Can you see the normal waveform?
Measure waveform at C112,C118 because it’s more easy to check.
Can you see the normal waveform?
LH40/LH55 Trouble shooting guide – AV
YES
Video
NO
This board has big problem because Main chip(LGE3159) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
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?
YES
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
Main chip(LGE3159)
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(LGE3159)
YES
Check JK1206
Can you see the normal waveform?
Can you see the normal waveform?
JK1206 may have problem. Replace this Jack.
Check the input (Pin R1,R3,P2 and Pin V1,V2,U1)
of LGE3159(IC100).
Measure waveform at C101,C102,C103 and C115,C116,C117
because it’s more easy to check.
Can you see the normal waveform?
of LGE3159(IC100).
Measure waveform at C101,C102,C103 and C115,C116,C117
because it’s more easy to check.
Can you see the normal waveform?
LH40/LH55 Trouble shooting guide – Component
YES
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
Main chip(LGE3159)
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(LGE3159)
This board has big problem because Main chip(LGE3159) have some troubles.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
After checking thoroughly all path once again, You should decide to replace LGE3159 or not.
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