Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
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TROUBLESHOOTING
1. TV/CATV doesn’t display.
Check TU1 Pin 16 (Video out put).
Can you see the normal signal?
Check the input (Pin 1) of LPF (IC808).
Can you see the normal waveform?
Could you measure voltage of TU1 & IIC
lines? Are they all normal?
You should replace TUNER.
Yes
No
Yes
Yes
Check the input (PinAN16) of BCM355x
(IC100). Measure waveform at C658
because it;s more easy to chek.
Can you see the normal waveform?
You should check power line
& IIC lines
No
After checking video signal line & the Power of
LPF you should decide to replace item or not.
No
Check the output (Pin 1) of LPF(IC808).
Can you see the normal waveform?
Yes
Yes
After checking Power of LPF you should decide
to replace item or not.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking throughly all path once again,
You should dicide to replace BCM355x or not.
No
2. Video doesn’t display.
Check JK701, JK707.
Can you see the normal waveform?
Check the input (PinAN17, AM19) of
BCM355x (IC100). Measure waveform at
C651 because it’s more easy to check.
Can you see the normal waveform?
JK701, JK707 may have problem.
Replace this Jack.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking throughly all path once again,
You should dicide to replace BCM355x or not.
No
