LG MULTI V IV ARNU07GTU 2 Series Service Manual page 113

Error
Error Type
No.
57*
Master 571
Communication error : Main
Slave1 572
PCB --> Comp PCB
Slave2 573
Slave3 574
n Error diagnosis and countermeasure flow chart
Are there any
communication wire
connections normal?
Yes
Is Comp PCB
assembly
normal?
Yes
Is there any error
when power reset?
No
Recheck power and
installation condition
Main PCB
Comp PCB
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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 Comp PCB
Yes
1. Replace Main PCB
C/Box Bottom
- 113 -
Troubleshooting Guide
Main Reasons
1. Bad Connection Between Comp PCB and
Comp PCB
2. Communication Wire Noise Effect
3. ODU Main PCB Damage
4. ODU Main PCB Damage
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