LG 75SJ857A Service Manual page 31

Standard Repair Process
Error
symptom
1. Remote control(R/C) operating error
Check R/C itself
Normal
operating?
Operation
N
Check R/C Operating Check & Replace
When turn off light Baterry of R/C
in room
If R/C operate,
Explain the customer
cause is interference
from light in room.
Replace R/C
D. Function error
Remote control & Local switch checking
☞A22
Check & Repair
Y
Cable connection
Connector solder
Y
Normal
Close
operating?
N
☞A22
Check B+
N
Normal
3.5V
operating?
On Main B/D
Y
☞A18
Close
Check 3.5v on Power B/D
(Power B/D don't have problem)
10
Established
date
Revised date
☞A22
Y
Normal Check IR
Voltage?
Output signal
N
Replace Power B/D or
Replace Main B/D
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10/16
Replace
Main B/D
Y
Normal
Signal?
N
Repair/Replace
IR B/D