Re: AS/400 UPS
Had a SUN E10K to run hot, read instructions, find filters need to be cleaned once a month or 3.. ask admin and get a "what filters?" response, obviously at that moment i had just volunteered to do the cleaning.
So we shutdown the thing as it had been running for over a year and we were scared of moving the filters and have everything sucked up, clean filters, turn back on.
Resulted in 3 HDDs, a switch and two of the fans (if i remember right) not getting back online, but redundancies worked pretty well at the time.