LG 50PG70F-UB (CHASSIS:PU82C) Service Manual ▷ View online
- 13 -
TROUBLE SHOOTING GUIDE
Component doesn t display
Check JP7001,J7015.
Can you see the normal waveform?
Check the L700, L704.
Can you see the normal waveform?
Check the C638, C628 in front of BCM3553.
Can you see the normal waveform?
YES
YES
NO
JK700, JK702 may have problem. Replace this
Jack.
NO
Replace the Part (L700, L704)
NO
After check the pattern between L703 and C651,
You can suspect that PCB is bad.
YES
This board has big problem because Main
chip(BCM3553) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM3553 or not.
- 14 -
TROUBLE SHOOTING GUIDE
Check JP7032,JP7033,JP7034.
Can you see the normal waveform?
Check the C635, C636, C637 in front of
BCM3553.
Can you see the normal waveform?
YES
NO
JK705 may have problem. Replace this Jack.
NO
After check the pattern between input of
BCM3553 and JK705 ,
You can suspect that PCB is bad.
RGB_PC doesn t display
Check JP7029,JP7030.
Can you see the normal waveform?
YES
NO
JK705 may have problem. Replace this Jack.
YES
This board has big problem because Main
chip(BCM3553) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM3553 or not.
- 15 -
TROUBLE SHOOTING GUIDE
HDMI doesn t display
Check input connect JK602.
Can you see the normal waveform?
Check DDC communication lines(IC601
Pin5,6)
Check the input of PI3HDMI341ART(IC600),
& IC703(TMDS141RHAR, HDMI4)
This signal is TMDS.
Can you see the normal waveform?
YES
YES
NO
JK602 may have problem. Replace this Jack.
Check the output of PI3HDMI341ART(IC600
) & IC703(TMDS141RHAR, HDMI4).
Can you see the normal waveform?
YES
Check the input and output of BCM3553.
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
NO
After checking the trace of TMDS lines and power of
PI3HDMI341ART & IC703(TMDS141RHAR, HDMI4), you
should decide to replace PI3HDMI341ART &
IC703(TMDS141RHAR, HDMI4) or not.
NO
YES
This board has big problem because Main
chip(BCM3550) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM3550 or not.
After checking the Power of this chip, you
should decide to replace this or not.
After checking the Power of PI3HDMI341ART or
TMDS141RHAR. you should decide to replace
PI3HDMI341ART & TMDS141RHAR or not.
YES
Check HDCP communication lines(IC102
Pin5,6)
NO
After checking the Power of this chip, you
should decide to replace this or not.
- 16 -
BLOCK DIAGRAM
Block Diagram - Overview
Flash
(16MB)
74LVC14APW
CS5345
(Audio
SW/ADC/OP_A
MP)
MTV416
(Micom
)
NTP3000
(Digital AMP)
X-tal(54M)
PI3HDMI341ART
(3x1,S/W)
EEPROM
AT/NT
Tuner
64Bit I/F
Reset
CVBS
Y/
Pb
/Pr
R/G/B
H/V Sync
RGB-PC
HDMI
0/1/2
COMP 1
COMP 2
AV 1
AV 2
RGB-PC
Audio L/R
I2S
MNT out
( L/R)
SPDIF OUT
I2S
RS-232C
Dead IC when Standby
Option
Alive IC when Standby
Video
Audio
Video
Front
End
Dual
HDMI
Rx
HD/SD
Video
Encoder
Audio
DSP
BCM3552(HD)/3(FHD)
MCLK
MCLK
HDMI CEC
HDMI CEC
(To Micom
)
To Micom
SDA
SCL
SIF
IF(AT)
Buffer
Single Channel
Digital out
(W)XGA
Local KEY
IR
Buffer
Buffer
24C16
AGC CTL (From BCM)
USB2.0
I2S Audio Input
VSB/QAM/NTSC/SIF
DDR(128MB)
CVBS/Y/C
CVBS
FHD
Dual Channel
Y/
Pb
/Pr
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