LG 42LY99-ZC (CHASSIS:LD75C) Service Manual ▷ View online
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4-2. In case of does't display the screen into specific mode
(1) Symptom
- There is no screen display from specific input mode.
(RF, AV, Component, RGB, DVI).
(2) Check following
1) Check the all input modes have normal display.
2) Check the Video(Main)/Data(Sub), Video(Main)/Video(Sub) have normal display from
2) Check the Video(Main)/Data(Sub), Video(Main)/Video(Sub) have normal display from
the PIP mode or DW mode. (Re-Check it Swap)
(3) In case of becomes unusual display from RF mode
Is the Tuner
normal?
Is the Input voltage, IIC Communication
and CVBS output normal?
and CVBS output normal?
Replace the Tuner.
Is the Tuner Cable
connected?
Re- inserts the cable.
Yes
No
No
No
Yes
Is the CXA2069Q
normal?
Replace the IC.
Is the Input voltage, IIC Communication
and HV sync normal?
and HV sync normal?
Yes
No
No
Replace the IC.
No
Is the FIL8548
normal?
Is the Input voltage, IIC Communication
and HV sync normal?
and HV sync normal?
No
Block A
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(4) In the case of becomes unusual display from side S-video/AV mode
Is Videoinput
of the AVJack(P1400)
normal?
Check the input source.
Are the Input voltage, IIC Communication
and HV sync normal?
and HV sync normal?
Yes
No
No
Replace the IC.
No
Replace the IC.
No
Is the CXA2069Q
normal?
Yes
Same as Block A.
(5) In the case of becomes unusual display from Component, RGB mode
Are the
R,G,B input and
H,V Sync of the J1100
normal?
Yes
Check the input source.
No
Same as Block A.
(6) In the case of becomes unusual display from HDMI mode
Is the
HDMI002 (IC1004)
normal?
Yes
Is the Input voltage, IIC Communication
and HV sync normal?
and HV sync normal?
No
Same as Block A.
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(7) In the case of becomes unusual display from SCART1 mode
Is Video input
of the A/V jack(J1200)
normal?
Yes
Check the input source.
No
Same as Block A.
(8) In the case of becomes unusual display from SCART2 mode
Is Video input
of the A/V jack(J1201)
normal?
Yes
Check the input source.
No
Same as Block A.
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5. In case of no sound
(1) Symptom
1) LED is green.
2) Screen display appears but there is no sound.
2) Screen display appears but there is no sound.
(2) Check follow
is there no
sound for all input
(modes)?
Is the speaker on?
Set on speaker in
menu.
Is the speaker
Cable normal?
Check the Speaker
Cable.
Cable.
Is the IC1300
operating normally?
Replace IC1300
(MSP4450)
Is the IC1301
operation normally?
Replace IC1300
(STA335BW)
Replace VSC B/D.
Yes
No
Is there no sound
only for HDMI?
Yes
Download the EDID data.
No
No
No
No
No
Only RF is
no sound?
no sound?
Yes
Check the Tuner IN/OUT
No
Check the signal before
CXA2069 refer to circuit diagram
CXA2069 refer to circuit diagram
Is there
no sound only for
AV/ Component/ PC
input?
Yes
Is there
no sound only for
specific input? (except
HDMI,DTV,RF)
Yes
Is the output of
CXA2069 normal?
Check the signal after CXA2069
refer to circuit diagram.
refer to circuit diagram.
No
Replace CXA2069
No
Yes
Yes
Yes
Yes
No
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