Comentário oficial
We have been tracking cases of those reporting problems with the SX3 after the voltage regulator was repaired (the "black dot fix"), and while it's difficult to nail down, most of the problems seem to be due to the host computer (and in the majority of cases, it's the graphics adapter driver causing an audio interrupt).
Either way, please file an inquiry ticket here and our support team will be able to gather some additional information to assist you in resolving this issue.