Things to keep in mind when replacing a PS on SF6800/6900
What could be easier than swapping a power supply?! True, very true but not when you’re dealing with SF6800/6900. The problem rises from the fact that it’s quite tough to insert a PSU into its bay because of a tight fitting. And there is a chance to make a pause during the insertion that could lead to a momentary drop in the 56V power line inside the server because not all pins have been connected to the power centerplane. And as a result, say goodbye to all of your domains and be prepared to power cycle.
To avoid that an engineer should try to insert a power supply in one smooth and uninterruptible motion. Thankfully, this issue has ben resolved with power supply 300-1595-03 and with the release of power supply 300-1930-01. So if you’re dealing with one of them then you should be safe.
Refer to the following link for more details.