How to Build: Mechanical Discordia

I'd think a cumulative Drain; very small amount, very long recovery time.

Transform would work but I always avoid it like the plague if there is any other way to do it.

1.  Dunno.  I'd probably use this as the combat build and simply note that it drains at a much slower rate out-of-combat.  Or use Side-Effects, maybe, if you want it to drain faster in combat.

2.  This is Drain; not dispel.  The SFX are up to you; it could visibly whither the item, or be functionally invisible.  We aren't making anything go away or even "breaking" the item; we are saying that this person has a quality or aura which causes complex objects they use to break or malfunction.  Or that is my interpretation.

3.  BECAUSE REASONS.  It is a habit from 4E; where basically, if we couldn't figure out how to build it, we built a transform, and I dislike jumping to that power unless it actually seems to apply.  So I try to only use transform if I am *actually changing something to another thing.*  I don't think that is the best way to reason from effect on what you describe; though it could certainly work.  Transform is kind of a complex drain anywho; or at least it shares things like the return rate.  

You could reason this as "transforming a working item into a non-working item, which can be repaired as normal or will repair in time."  You could reason it as "an aura that causes complex items to break or fail."  Either of those could be built as a Drain, or a Transform.  

Of particular note is that Drain is going to be concerned with the AP of the affected item, while Transform is only going to care about the BODY of the item.  

This implies, to me, that Drain is "better" - it will be less likely to immediately break a high-AP power built onto a low-BODY focus.

Ah yes, I read Drain as Dispel in my head for some reason. As to your last sentence, yeah that is the opposite of what I want this to do. The more fragile the object, regardless of it's actual power build, the quicker it would seize. This is all about the mechanical bits becoming immobile, like being fossilized, or gears rusting together, or an engine seizing up because of lack of oil, etc. which is why I felt Transform might actually be more appropriate.

It's something I'm still tossing around. The idea is for it to be a disadvantage and not something they can use to their advantage. But I can already see how a PC would use it to their advantage with the increased drain rate during combat and how it wouldn't be effective enough to stop them from using mechanical devices in combat without the increased drain rate.