Here is the Kenson answer to my nullify question
http://www.atomicthinktank.com/viewtopic.php?p=262858#262858
FWIW, I do use Nullify for just the sort of thing you're talking about, the modifiers involved pretty much come out in the wash:
Affects Objects +1 (detailed in Ultimate Power, but basically means the effect works on objects as well as creatures)
Only Affects Objects –1 (so net +0 modifier)
Objects don't make Will saves, so use the opposed power rank check instead, using the item's highest rank.
Also note that some equipment won't "restart" on its own: it'll need repair, resetting, or at least someone to hit the "on" switch again. (This is just a descriptor and part of the limitations of equipment.)
So Nullify (Equipment Type) such as "Nullify Electronics" is what you're looking for, IMHO.