Tuesday, August 16, 2016

GSCC Reports HARD_BAD Due to Backplane Fault

Due to backplane faults, the GSCC board is not running properly and keeps reporting the HARD_BAD alarm. After the subrack is replaced, the alarm clears.

Fault Type

HARD_BAD

Symptom

The GSCC board keeps reporting the HARD_BAD alarm.

Cause Analysis

When parameter 5 in the HARD_BAD alarm parameters is 0x04, the NMS displays that an Ethernet communication port between boards is faulty. There are three possible causes:
  1. The GSCC board is faulty.
  2. The auxiliary interface board is faulty.
  3. The backplane is faulty.

Procedure

  1. Remove the standby GSCC board. The HARD_BAD alarm persists. So, the fault should be located on the active GSCC board, auxiliary interface board, or slot 17.
  2. Replace the active GSCC board in slot 17. The HARD_BAD alarm persists. So, the active GSCC board cannot be faulty.
  3. Exchange the active GSCC board in slot 17 with the standby GSCC board in slot 18. The standby GSCC board in slot 17 reports the HARD_BAD alarm. So, the fault should be located on the standby GSCC board, auxiliary interface board, or slot 17.
  4. Replace the standby GSCC board in slot 17. The HARD_BAD persists. So, the standby GSCC board cannot be faulty.
  5. Replace the auxiliary interface board. The HARD_BAD alarm persists, so the fault does not pertain to the auxiliary interface board. The fault should be located on slot 17.
  6. Check whether the backplane has bent pins.
  7. Replace the subrack. The HARD_BAD alarm clears.

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