Troubleshooting Guide - LG FLATRON L2320A Service Manual

NO POWER
(POWER INDICATOR OFF)
Check Stand-by
5V on Power B'd
Pass
Check Ctrl signal
'PCB-PWR'
Pass
Check
Reset signal for U43
(AV B'd :
U801 Pin#8)
Pass
*Check the PND
Cable connection
*Check the B'd to B'd
connection
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Only for training and service purposes

TROUBLESHOOTING GUIDE

1. OUT OF ORDER ON POWER
Check
Fail
Connector or
5V Output
On Power B'd
Pass
Check
Fail
18.5V Output
On Power B'd
Pass
Check
DC/DC Converter
Output
Pass
Check I2C Line
NCTL & PCTL
Level : >4V
(U43 Pin2, 3, 4, 5 )
Pass
- 13 -
Fail
Fail
Fail
Trouble
on NCTL
Fail
Check Point
Trouble
on PCTL
Replace
the Power B'd
Replace
the Power B'd
Check Device
AV B'd
:U803,U804,U805
Bridge B'd : U905
Check Device
Main B'd :
U3,U4,U43,U44,U12
AV B'd : U702
Bridge B'd : U904
Key-control B'd : U1,U2
Check Device
Main B'd :
U3,U4,U43,U44,U12
AV B'd : U601,U302
Audio B'd : U3
LGE Internal Use Only