Samsung AC052FCADEH - AC Zero Cross Signal Error

Samsung Electronics 4-47
4-4-17 AC zero cross signal error
1.Checklist :
1) Check the power condition at customer's house (Is there any power noise?)
2) Have been there power failure?
2. Troubleshooting procedure
Terminate the service
No
Is the AC line zero cross signal error appeared
again?
Exchange the Outdoor PBA
Restart after power off
Yes