So, a DIY setup. I guess that when you are making a production model (ex: iMac), this is the kind of thing you have to test for. We had an interference problem

So, a DIY setup. I guess that when you are making a production model (ex: iMac), this is the kind of thing you have to test for. We had an interference problem at work once, in a VME rack, an I/O board with a particularly large coil was messing with the CPU board, solved by moving the offending board in another slot. The effect was mostly random crashes and reboot though, nothing fancy like a keyboard layout change.