Read LG 32LB9DE (CHASSIS:LA75C) Service Manual online
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TROUBLESHOOTING
1. TV/CATV(Analog) doesn’t display
2. Video doesn’t display
Chec k TU 1 Pin 23( Vid eo o ut p ut )
Can yo u s ee t he n o rm al s ig nal?
Chec k t he in p ut ( Pin 1) o f Lo w -Pa ss
Filt er ( IC808) .
Can yo u s ee t he n o rm al w avef o rm ?
Can yo u s ee t he n o rm al w avef o rm ?
Chec k t he o ut p ut ( p in 8) o f Lo w - Pa s
s
Filt er( IC808) .
Can yo u s ee t he n o rm al w avef o rm ?
Chec k t he Cap ac it er( C658) in f ro n t o f
BCM3552 c hip .
Can yo u s ee t he n o rm al w avef o rm ?
YES
YES
YES
NO
Co uld yo u m eas ure VCC vo lt ag e( 5Pin ) o f TU 1 &
IIC lin es ( 8, 9Pin )
IIC lin es ( 8, 9Pin )
Are t hey all n o rm al?
?
YES
Yo u sho uld rep lac e TUNER.
NO
Af t er c hec ki ng t he C800( 0. 1uF Cap ) ,
yo u c an s us p ec t t hat PCB is b ad .
NO
Af t er c hec ki n g t he Po w er o f Lo w-Pass Fi lt er yo u
s ho uld d ec i d e t o rep lac e Lo w- Pa s s Fi lt er o r n o t .
NO
Af t er c hec ki n g t he p at t ern b et w een p in 8 o f IC808 and
C658, yo u c an s us p ec t t hat PCB i s b ad . .
YES
This b o ard has b ig p ro b lem b ec aus e Mai n
c hip ( BCM3552) have s o m e t ro ub les .
Af t er c hec kin g t ho ro ug hly all p at h o n c e ag ain ,
Yo u s ho uld d ec i d e t o rep lac e BCM3552 o r n o t .
Yo u s ho uld d ec i d e t o rep lac e BCM3552 o r n o t .
Chec k JP7004.
Can yo u s ee t he n o rm al w avef o rm ?
Chec k t he R707.
Can yo u s ee t he n o rm al w avef o rm ?
YES
YES
NO
JK701 m ay have p ro b lem . Rep lac e t hi s Jac k.
Chec k t he C651 in f ro n t o f BCM3552 c hip.
Can yo u s ee t he n o rm al w avef o rm ?
NO
rep lac e Part ( R707) .
YES
Thi s b o ard has b i g p ro b lem b ec aus e Mai n
c hip ( BCM3552) have s o m e t ro ub les .
Af t er c hec ki n g t ho ro ug hly all p at h o n c e ag ain , Yo u
s ho uld d ec id e t o rep lac e BCM3552 o r n o t .
NO
Af t er c hec k t he p at t ern b et w een R707 an d C651,
Yo u c an s us p ec t t hat PCB is b ad .
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