That's the whole thing. It seems that with Ketron, sometimes it is a bug that will affect every unit, and other times it is a hardware/quality control issue that won't affect every single unit. I updated my SD4 and SD40 yesterday, and I still have a USB issue with the SD4. I was reading on the vArranger forum that some units have the issue and others don't. The SD1000 has the same issue; some units can be powered by USB only, many others don't. Someone found out that it was some cheap part in it.
"You Shall Know the Truth, and the Truth will set you free." John 8:32