Hello there. I'm having technical problems with one of my Vistas and am hoping to get a little troubleshooting advice. I noticed that one speaker powers off and does not play, while the other is fine. I tried unplugging and plugging it in again and it does power on again, with a dimmer blue light than the other speaker. Within a few minutes it turns off again. I've replicated this a couple of times and it does the same thing. I swapped the speakers and the defective one did the same thing on the other side. There haven't been any power surges. Any clues as to whats going on? Thanks