Of all the users of Parker DriveBloks, we seem to be the only ones that experience frequent capacitor failures. Of the failures we have, only the thrusters that go through the RTU (and its sliprings) seem to suffer.
Solution: bypass the sliprings by drilling a hole in the fairing for the cable. As a safety precaution against continuous rotation of the RTU (disabled in software, but... you never know), we aren't using the plastic shells to hold the cables together.