LG ACHH Series Manual page 85

Error number Errors
75 Fan CT sensor
(751) defect
n Failure diagnosis method
Is input voltage normal?
Yes
Is a fan board normal?
Yes
Is an error still
occurred even if the
power is reset?
Yes
Power and installation
environment recheck
Check DC input power 15V on Inverter PCB.
Meaning
In case where micom
input voltage of the top
current at the fan motor is
out of 2.5 V ± 0.3 V range
Confirm input power 15 V wire connection status →
No
Re-assembly and take action when finding a problem
No
Fan board replacement
No
Confirm whether or not a fan board IPM is normal
→ Fan board replacement
Main cause of occurrence
1. Input voltage 15 V abnormality
2. Power wire disconnection and connector contact defect
3. Fan board defect [CT sensor detection part]
4. Inverter board defect [DC power part]
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Error code check