Apologies for bringing back a dead thread, but I have an update. It turns out that I was getting audio with headphones/speakers attached, but nothing through the internal speaker. My solution was to leave a set of speakers attached. To avoid wasting electricity, I left them unplugged when the CC was off, adding a small annoyance of needing them plugged in and dedicated to this purpose.

Anyway, turns out that the best solution was to leave the machine off for a few months. Turned it on yesterday, heard the chime, and did a double take because I was standing between the speakers and the CC--the sound was coming from the CC. I am happy to have a 100% working CC II (at least for now ) even if I can't pinpoint why it's working.