Fixing an Intermittent Left-Half Failure on the Kinesis Advantage360

A follow-up to my earlier post on programming a Dvorak layout for the Advantage360. Same keyboard, different problem: the left half of my wired Advantage360 (KB360, SmartSet engine — not the Pro) started dropping out a few times a day. If you’re seeing the same thing, this post is the short version of how I diagnosed it and what fixed it.