LG MU-42PM11, Service Manual

Page: 17 / 42

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TROUBLE SHOOTING GUIDE
3. Protect Mode
(1) Symptom
¯
Will not fully turn on
¯
The Relay "clicks"
¯
Front LED changes from Green to Red
(2) Check follow
Is the Power Board
good?
Replace Power
Board.
Is output the normality Low/High
voltage except Stand-by 5V?
Yes
No No
Are all connectors
connected?
Replace
connector.
Replace
Y-Board.
After connecting each connector well,
is operation good?
Yes
No No
Is the Ctrl Board
good?
Replace
X-Board.
Is the output voltage good after
removing P1, 2, 101, 300, 701, 702
connector of Ctrl-B/D?
Yes
No Yes
Is the Y-Board good?
Is the output voltage
good after removing
P5, P6 connector of
Y-B/D?
Check Fuse(F52) on Y-B/D?
(In case of open, replace fuse)
Yes
No Yes Yes
Replace
Z-Board.
Is the Z-Board good?
Is the output voltage
good after removing
P1 connector of Z-
B/D?
Check Fuse(FS1, FS2) on Z-B/D?
(In case of open, replace fuse)
Yes
No Yes
Is the X-Board good?
Is the output voltage good after
removing P1, 2, 3, 4, 6, 7 connector
of X-B/D?
If after removing P1, P2, P3, P4 the output
voltage is normal: Replace Right X-B/D.
If after removing P6, P7 the output voltage
is normal: Replace Left X-B/D.
Yes
No Yes
Is the VSC Board
good?
Is the output voltage good after
removing P1000, P1200?
After crisis COF of each board, check the normality operates.
If in case normality operates, correspondence COF Fail is
replace the module.
If after removing P1000 the output is
normal: Replace Analog Board
If after removing P1200 the output is
normal: Replace Digital Board
Yes
No
Is normal the
COF of X, Y, Z?
No
Yes
Yes
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