Read Sharp LL-171G Service Manual online
LL-171A-W/B/LL-171G-W/B
TROUBLESHOOTING
5 – 2
Set volume to max and has the output
waveform appeared in 4, 9, 16, 21 of
U12 pin?
waveform appeared in 4, 9, 16, 21 of
U12 pin?
Is connection of from a main PWB cable
to key PWB and a speaker cable normal?
to key PWB and a speaker cable normal?
No
Speaker defective.
Yes
No
No
No
Yes
Yes
■
NO SOUND
■
Screen does not operate normally.
A
Screen does not operate normally.
Check RGB cable.
Defective
Replace RGB cable with
a new one.
a new one.
Check screen condition by changing display modes.
Operate the "ALL RESET" to check if screen condition changes.
(Press and hold MENU and SELECT buttons while turning on power switch.)
(Press and hold MENU and SELECT buttons while turning on power switch.)
Screen stays in black.
Screen stays in white.
Screen jitters or on-screen
characters flicker.
characters flicker.
Abnormal color
Check the following signals
1) Check if module control signal is output (U10).
2) Check if VLCD voltage is output normally.
Yes
No
Yes
No
Yes
No
CLOCK and PHASE
can be adjusted?
can be adjusted?
Does abnormal area move on
screen when BLACK LEVEL or
CONT is changed after H-POS
or V-POS is set?
screen when BLACK LEVEL or
CONT is changed after H-POS
or V-POS is set?
Switch PWB defective
Main PWB defective.
LCD panel defective.
No sound
Audio cable defective.
Yes
No
U12 defect and so
Audio PWB defective.
Audio PWB defective.
Yes
Normal
Defective
Is the 7, 8, 19 pin of U12 about 12V?
Power supply inverter
PWB defective.
PWB defective.
Check
3, 22pin of U12 signal
3, 22pin of U12 signal
Has the input waveform
appeared in 5, 23 pin of U12 ?
appeared in 5, 23 pin of U12 ?
U601 of Main PWB defect and so
Main PWB defective.
Main PWB defective.
Is the signal outputted normally
from the source of an Audio signal?
from the source of an Audio signal?
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