BUS_ERR alarms appeared on OSN 3500 and OSN 1500

BUS_ERR alarms appeared on 2 different NEs which were OSN 3500 and OSN 1500. 

BUS_ERR 
The reason of this alarm was because on the backplane of both NE OSN 7500 and OSN 1500, there were bend pin corresponding to the boards which were having this alarm. 
N/A1. We prepared one SSN1SCCA01 board, and the version is 9.74, another SSN4SL6405 board, and the version is  
    8.04 
2. We Plug out the slot 10 board, 
3. We insert the new slot 10 board, and monitor whether the BUS_ERR alarm disappear – NO 
4. We plug the slot 11 board 5. 
5. We iInsert the new slot 11 board, and monitor whether the BUS_ERR alarm disappear – NO 
6. We Switch the XC boards, and check the switch whether successfully – YES 
7. We  Plug the slot 9 board, 
8. We Insert the older slot 10 board and monitor whether the BUS_ERR alarm disappear after the HSC_UNAVAIL alarm disappear 
 NO 
After doing all this steps above, the problem was the same. Then from detail observation , we noticed the there were bend pin on the backplane in both OSN. (can check attached ms word file) 

We changed the subrack for both NE OSN, and the problem no longer exist. 

This problem was a hardware defect which could be useful if same problem happens to carefully check the backplane also. However please can only check the backplane after getting proper permissions and after all troubleshooting using NMS and effort to clear alarm does not work has been done.

Sometimes front line engineer may just think and check for mismatch version or wrong configuration.