To clarify, smaller iMac has 10.1.1, Powermac has 10.1.0, larger iMac now has 10.6.2. I spoke to Apple and the guy questioned whether the Powermac should have the software upgraded to 10.1.1, but that makes no sense to me, since all three were fine till I installed the Time Capsule, and even the one with 10.1.1 keeps losing the connection. The only difference is that it sees the network, whereas the Powermac does not see it at all.