I have a pair of 3Com 4200 Superstack III switches stacked together. One is a 4226T and the other a 4228G. The only real difference is that the 4228G has two ports that I can use for fiber connections (one of which is occupied for a link over to a different building). The 4228G is unit 1, and the 4226T is unit 2.
Today, for some unkown reason, I can no longer see unit 2 in the stack. I can move the stacking cable back and forth to swap unit numbers, and both ends will use the new number. So something is working. But anyone plugged in to the 4226T can't see the rest of the network, and both the web and telnet administration interfaces from the 4228G now just show a single unit.
Any ideas what might be going on?