LG 37LF7700 Service Manual ▷ View online
- 29 -
5. In case of no sound
(1) Symptom
1) LED
is
blue.
2) Screen display but sound is not output
(2) Check follow
All input(mode)
is no sound?
No
Is VCC “+16V or +20V”
Normal?(JP1 : 1pin)
Yes
No
Replace Power Board.
Yes
Is the speaker Cable
normal?
normal?
No
Check the Speaker
Cable
Cable
Only HDMI is
no sound?
Download
the EDID data.
No
No
Only DTV is
no sound?
No
Yes
Check the Tuner In/Out
Yes
Only AV/component/PC
input is no sound?
No
Check the input source.
Yes
Replace Main Board.
- 30 -
6. Exterior view defectiveness
(1) Check follow
Damage LCD module?
Replace LCD Module
No
Damage cabinet?
No
Yes
Yes
Replace cabinet
Yes
Damage RCU?
Replace RCU.
No
Replace stand
Scratch Stand?
Yes
- 31 -
BLOCK DIAGRAM
- 32 -
WIRING DIAGRAM
1. 32LF7700-ZC
2. 37LF7700-ZC
Main Board
Ass y
(P/No. : EBU60703401)
LIPS
(LCD Inverter
Power Supply)
Power Supply)
(P/No. : EBU60703601)
MAIN to IR&Intelligent
(P/No. : COV30100801)
Inverter Slave Cable
=> Contact with P401
(P/No. : COV30100503)
KEY
BOAR
D
CH-
CH
+
TV
/A
/A
V
Men
u
V-
V+
CO
N
(P/
N
N
o. :
EBR
EBR
488
47001)
IR&Intelligent
BOARD
(P/No. : EBR42600102)
CO
N
CO
N
JP471
JP
2
2
JP261
Intelligent B/D to Bar Shield Left
(P/No. : COV30100401)
JP1
P201
LIPS to MAIN B/D
(P/No. : COV30100302)
Speaker Woofer
(P/No. : EAB41280401)
SC101
Noise Filter
(P/No. : EAM36140904)
Inverter Master Cable
=> Contact with P402
(P/No. : COV30100502)
Speaker Twitter
(P/No. : EAB41284401)
SPK Cable
(P/No. : COV30100701)
STBY
LCD T-CON BOARD
(P/No. : EAT60663401)
CON
P401
CON
P402
CON
LVDS Cable
@ F-HD/ 50Hz
(P/NO. : COV30100601)
LCD PANEL
LC370WUE-SBB2
(P/No. : EAJ59211901)
Noise Filter to SMPS
(P/No. : COV30100401)
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