How to replace a failed ISR4351?

[dj010166]

I have a failing ISR4351 and my RMA is on the way. I’ve never replace one of these before. Any instructions and tips out there?

[MHM Cisco World]

@Leo Laohoo can support you in this task.

[Richard Burts]

I am not clear whether the description that it is failing means that it is still running, or is it dead? If it is still running then immediately get a copy of the running config from the old router. If it is dead do you have a recent copy of the running config?

[dj010166]

It is still running. It lost power and had problems with tunnel20 afterwards. TAC says the router needs to be replaced. I will get the running config tonight. Thanks

[Leo Laohoo]

1.  Power up the replacement unit and make sure it is working.  (Stupid, but yes, over the span of 10 years, I have had two replacement unit arrive dead.)
2.  Make sure to upload the same firmware version, currently being used by the failed unit, into the new unit. 
3.  Licensing is one of the biggest pitfalls.  Review the license activated in the failing unit and compare it with the replacement unit (after the replacement unit has it's firmware updated).  
4.  Copy the config across to the replacement unit.  Re-generate the SSH crypto key.