Just out of curiousity, what was the amperage of the new one? If it was too low (I don't even know what the SVX is supposed to have), then that's probably your problem. I replaced the alt in my XT6 with a new one from AutoZone. Took me about 2 days to basically melt the contacts and turn the copper windings a nice powdery white. Yee-ha.
Anyway, it turns out that they gave me a 75amp one (Mitsubushi no less
) that was about 50amps shy of what it needed, because it was for an XT. And considering the rarity of the SVX, it wouldn't surprise me if the mom & pop place didn't know what they were giving you, and gave you one for an Impreza or something. Just a thought.