LG MULTI V Service Manual page 132

Self-diagnosis function
Error
Error Type
No.
Communication error : Main
57
PCB --> Inv. PCB
n Error diagnosis and countermeasure flow chart
Are there any
communication wire
connections normal?
Yes
Is Inv. PCB
assembly
normal?
Yes
Is there any error
when power reset?
No
Recheck power and
installation condition
Main PCB
Error Point
Failing to receive inverter
signal at main PCB of
Outdoor Unit
No
1. Check communication wiring conditions
2. Check connector conditions
→ Rewire them if abnormality found.
No
1. Replace Inv. PCB
Yes
1. Replace Main PCB
- 132 -
Main Reasons
1. Bad Connection Between Main PCB and
Inv. PCB
2. Communication Wire Noise Effect
3. ODU Main PCB Damage
Inv. PCB
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