Once, one of the electronics magazines to which he subscribed had published a joke circuit which
was guaranteed not to work. At last, they'd said in an amusing way, here's something all you ham-fisted
hams out there can build in the certain knowledge that if it does nothing, it's working. It had diodes the
wrong way round, transistors upside down, and a flat battery. Newt had built it, and it picked up Radio
Moscow. He'd written them a letter of complaint, but they never replied.
The above quote describes someone a character in a novel who has a unique gift (or lack thereof) when it comes to dealing with technology. Rereading the passage made me wonder about this sort of thing in the context of wizardry.
Hexing breaks technology. That is to say, successfully hexed technology can fail in a number of ways, but the only guarantee you have is that the technology will stop working as intended.
So, what happens when you hex technology that was made to not do anything? It can't just keep not doing anything; if hexing worked like that, you'd see a lot more things like hexing a gun drop the maximum range of the fired bullets by 10%. The way hexing works is to change machinery so that it no longer works as it was made to work. So, presumably, an enterprising wizard could build a computer by meticulously collecting computer parts that were engineered not to work, rigging them to fit together incorrectly, and then hexing it until you managed to randomly tune its nonfunctional state to "Work as intended (mostly)" and deal with the side effects.
The real danger of doing this sort of thing would be that you'd have only the vaguest idea what kind of broken state nonfunctional technology would end up in, since hexing it would also change it every time. Worse, while accidental hexing puts ordinary machines into a generally predictable state (not doing much of anything), hex-enabled technology could fire up at completely random times. Still, if you're the kind of wizard with big, big books on underlying theory and stubbornly maintain that the universe is rational and understandable, you might have a big-ass hex-enabled gun loaded with an bullet that can't fire as an emergency measure.