On an OptiX OSN 7500 NE, the active and standby N2GSCC boards report the POWER_ABNORMAL alarm with parameters 0x06 0x00 0x01 0x00 0xff. The version of the OptiX OSN 7500 is 188.8.131.52.
1. See the SCC Deployment Guide for the OptiX OSN 7500 for the alarm parameters. The parameters indicate that the AUX receives a voltage higher than 3 V.
2. Replace the AUX with a normal AUX board. The fault persists.
3. Check the backplane. It is found that the backplane does not have any bent pin. Therefore, the fault is unassociated with the backplane. The power supply for the AUX is from the EOW and the EOW alarms are reported through the AUX. Therefore, check the EOW. It is found that the EOW supplies a voltage higher than 3 V.
5. Replace the EOW with a normal EOW board. Then, the fault is rectified.
The possible causes are as follows:
1. The AUX fails.
2. The SCC fails.
3. The EOW fails.
4. The backplane fails.