How to handle fautly grounding point casuing ADSL ports failed of ADLE board?

Issue Description

It was escalated by customer that they faced every day ADSL ports in failed state of ADLE boards.
The network connectivity is like this,

MDF>>MA5616>>SDH System>>BRAS

Version of MA5616 is as follows,
MA5616V800R307C01
Service Board Name          : H835ADLE

Alarm Information

NULL

Handling Process

1- Service boards found normal, only the ADSL ports are appearing as Failed and found on almost all ADLE boards of the MA5616.
2- Control Board found normal and there is no communication lost alarm between control board and service board.
3- There are chances of some exceptional surge from outside coming through MDF towards system causing ADSL ports failure. Initially we reset the chipset of board to restore the services and move to step 4.
4- We check the grounding point of system and MDF, it was not working and test result is as mentioned in snapshoot. The device was installed in switch room, we check the grounding values of MDF and switch room it was not according to standard and resistance values were too high. We also check the grounding point of other room (Transmission Room) in same building where SDH system was installed, its value was 1.31 ohm which is normal.



On investigating we found that the grounding supply of MDF and switch room is different from transmission room and grounding supply of MDF and switch room was actually not working. We connect the grounding cable of MDF and switch room to transmission room's grouding plate and issue resolved after that.


Root Cause

1- Service Board faulty.
2- Control Board faulty.
3- Exceptional surge from outside lines.
4- Grounding / Earthing point faulty.

Suggestions

For such kind of issues specially for Access Network, must check the grounding of the equipment and MDF. The equipment and MDF should be properly grounded and tested regularly the resistance value of grounding must be in the range around 1 to 5 Ohm.