The difference of POWER_ABNORMAL AND POWER_FAIL.
1. POWER_ABNORMAL is alarm of power fail. Generally, it indicates the fault inside the board.
2. POWER_FAIL is also the alarm of power invalidation. But this alarm only generated in SCC board for the cause of battery run out in board. This alarm does not affect service and can be eliminated by changing SCC board.
3. POWER_ABNORMAL on PIU board is caused by the abnormal voltage of power supply.