3COM Switch

Hi guys, hope you well.
Listen i have a little question for you, on my superstack of 3com switches i have only one of the switches that is loosing power to it, i.e the uptime is not the same as the rest, i have been trying to find the cos of it, but honestly no joy.
I have swapped the terminals from one switch to another and the problem followed, the uptime keeps on going down, i wonder could that be a device on the NT that would drop my switch or any help be great!

P.S. i did update firmware to most resent, and im running ups and rest of the stack through AC-filter.