I bought an Alesis SR16 here on TB. Turns out it doesn't work. I just (finally) got a new power supply, that didn't fix it. Power comes on, display comes up, but there's no sound. Patterns don't play, tapping the keys doesn't yield drum sounds. Volume is up (the problem is consistent at all volume levels). Any suggestions for things to try before I consign this to the "purchases that didn't work" bin?