LG 42LC2D (CHASSIS:LA63E) Service Manual ▷ View online
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TROUBLESHOOTING
1. TV/CA
TV doesn't display
Check TU4001 Pin9(Video output)
Can you see the normal signal?
Could you measure voltage of TU4001 & IIC
lines?
Are they all normal?
You should replace TUNER.
You should check power line & IIC lines.
Check the input(Pin63) of AV switch(IC5003).
Can you see the normal waveform?
After checking the Power of AV switch you should
decide to replace AV switch or not.
Yes
Yes
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Check the output(Pin56) of AV switch(IC5003).
Can you see the normal waveform?
After checking the Power of AV switch you should
decide to replace AV switch or not.
Check the input(Pin1) of LPF(IC4006).
Can you see the normal waveform?
After checking the Power of LPF you should
decide to replace LPF or not.
Check the output(Pin8) of LPF(IC4006).
Can you see the normal waveform?
After checking the Power of LPF you should
decide to replace LPF or not.
Check the input(PinH26) of BCM3550(IC4006).
Measure waveform at C1010 because it
’s more
easy to check.
Can you see the normal waveform?
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.
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2. V
ideo doesn't display
Check J5007 Pin3C
Can you see the normal waveform?
J5007 may have problem. Replace this Jack.
Check the input(Pin1 or Pin8) of AV switch
(IC5003). Pin1 is for video1,Pin8 is for video 2.
Can you see the normal waveform?
After checking the Power of AV switch you should
decide to replace AV switch or not.
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Check the output(Pin56) of AV switch(IC5003).
Can you see the normal waveform?
After checking the Power of AV switch you should
decide to replace AV switch or not.
Check the input(Pin1) of LPF(IC4006).
Can you see the normal waveform?
After checking the Power of LPF you should
decide to replace LPF or not.
Check the output(Pin8) of LPF(IC4006).
Can you see the normal waveform?
After checking the Power of LPF you should
decide to replace LPF or not.
Check the input(PinH26) of BCM3550(IC4006).
Measure waveform at C1010 because it
’s more
easy to check.
Can you see the normal waveform?
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.
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3. Component doesn't display
Check J5004,J5005.
Can you see the normal waveform?
J5004,J5005 may have problem. Replace this
Jack.
Check the input of Component
switch(IC5001,IC5002).
Can you see the normal waveform?
After checking the input TR of component, you
should decide to replace component switch or not.
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Check the output of Component
switch(IC5001,IC5002).
Can you see the normal waveform?
After checking the Power of component switch
you should decide to replace component switch or
not.
Yes
Check the input of MST3361(IC7004
Pin41,44,46).
Can you see the normal waveform?
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
Check the output of MST3361(IC7004 ).
Can you see the normal waveform?
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
Check the input and output of BCM3550(IC4006).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
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.
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4. RGB_PC doesn't display
Check input connect P7004.
Can you see the normal waveform?
P7004 may have problem. Replace this Jack.
Check the input of Component switch(IC5002).
Can you see the normal waveform?
After checking the input TR of RGBHV, you
should decide to replace these components or
not.
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Check the output of Component switch(IC5002).
Can you see the normal waveform?
After checking the Power of RGB switch you
should decide to replace component switch or not.
Yes
Check the input of MST3361(IC7004
Pin41,44,46).
Can you see the normal waveform?
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
Check the output of MST3361(IC7004 ).
Can you see the normal waveform?
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
Check the input and output of BCM3550(IC4006).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
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.
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