LG 42PT85-ZB (CHASSIS:PD74A) Service Manual ▷ View online
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Are the R,G,B input and H,V
Sync of the P1100 normal?
Check the input source
No
Is the HDMI002(IC1004)
normal?
Yes
Same as Block A
Are Input voltage, IIC Communication
and HV sync normal?
No
Is the Video input of the
A/V Jack(J1200) normal?
Yes
Same as Block A
Check the input source
No
Replace the IC.
No
Is the Video input of the
A/V Jack(J1201) normal?
Yes
Same as Block A
Check the input source
No
Yes
Same as Block A
(5) In case of an unusual display in Component, RGB mode
(6) In case of an unusual display in HDMI mode
(7) In case of an unusual display in SCART1 mode
(8) In case of an unusual display in SCART2 mode
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6. 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) Procedure check
All input(modes) have
no sound?
Is there no sound only
for HDMI?
No
Yes
Download
the EDID data
Check the signal after
CAX2069 refer to circuit diagram
No
Is there no sound only
for specific?
(except HDMI,DTV,RF)
Check the signal before
CAX2069 refer to circuit diagram
No
YES
YES
Is there no sound only
for RF?
Check the Tuner IN/OUT
No
YES
YES
Is there no sound only
for AV/component/PC?
Is the output of
CXA2069 normal?
No
YES
Is the IC1300
operating normally?
Replace the IC1300
(MSP4450)
No
Is the IC1301
operating normally?
Replace the IC1300
(STA335BW)
No
YES
Replace the VSC B/D
YES
No
Replace the CXA2069
Is the speaker on?
Set speaker on in the
menu.
No
Is the speaker Cable
normal?
Check the Speaker
Cable.
No
Yes
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7. Time shift Mode ( DVR BOARD )
(1) Symptom
1) Does not work time shift mode.
2) Can not enter to recorded list.
3) Can not record AV/RF.
2) Can not enter to recorded list.
3) Can not record AV/RF.
(2) Follow check
Is time shift mode on?
Are the cables connected?
(12pin, 4pin,40pin)
Re-insert the Cable.
Change the time shift mode
from off to on.
Yes
No
Yes
Yes
Yes
Yes
Yes
No
Is the Power B/D Is the
operating normally?
Is the Power & Data Cable
normally?(P1500, P1501)
Is the HDD normally?
Check the BU9580KVT
IC(IC1504) normally?
Check the STI1500 IC(IC100), NEC61151F(IC1600),
NEC64015A(IC1901) normally?
Check the power B/D or
Power connector(P901)
Change the power and
Data Cable
Connect 31pin cable.
Change the HDD
normally?
Replace the STI5100, NEC61151F,
NEC64015A normally?
Replace the VSC B/D
Yes
Yes
No
No
No
No
No
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8. Time shift sound and Recorded video sound ( DVR BOARD )
(1) Symptom
1) SOUND does not come out.
(2) Follow check
MUTE key on?
Is the Sound cable
normally?
Connect speak cable
Sound normally?
Turn off the mute key.
Are power cables
connected.
Connect power cables
/power B/D.
Yes
Yes
No
No
No
No
Yes
Yes
Yes
No
Is the 31pin
cable(P1501) normally?
Check the speakers
normally?
Check the MSP(IC1300),
Audio AMP(1301)
normally?
Connect the Data
cable.
Change the speakers.
Change the ICs
normally?
Change the VSC B/D.
Yes
No
No
No
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