After my fourth trip for repair, they replaced almost everything internal. Memory, key contacts, and most importantly, my vocalizer pre-amp. Guess what? The hiss everyone seems to have from the internal vocalizer? Now GONE. I don't know whether they changed the design or what, but it's GONE. I'm ecstatic.
My only two problems are for some reason I can't get reverb on my voice. I'm not sure what they did. Also in the guitar sounds, two of the newer ones:
Unplugged and oldcountry, now sound totally different. Electric instead of a different version of the acoustic folk guitar. Weird.