Two Cisco SUP720-3BXL

I let you guess what is the difference between these two Cisco SUP720-3BXL supervision cards ?
Two Cisco SUP720-3BXL

The one on the left is a regular functionning one, whereas the one on the right is a regular ... no more functionning one.

How to spend a Friday night making sure your backbone network is 100% operational and redundant and everything, instead of having a beer (or whatever you like).