From the third picture of the back box it looks like the bottom board is the wrong way which is funny since the DATA EAST on the board is facing up the way you have it and that would be logical. And I don't know this system well but looking from the tear down pictures that board is flipped the other way.

You're working on your BTTF and not mine?

What is the cylinder on the lower right in the cabinet box?

I believe that was their attempt at creating a more bassy sound in the cabinet

Thanks for the paint info earlier. I am soooo jealous that I'm not at this stage of my BTTF cabinet refurb! Your 'uh oh' moments are exactly what I'm finding most useful. Not that I'd wish that upon you but they're clearly things I'd stumble into myself. So, thanks in advance! One thing I was expecting to do, and which I've now confirmed by looking at your pics, is that I plan to paint the interior bottom portion of the cabinet white with blue where you have it. I think it looks cleaner, makes the interior brighter, and much easier to find all those little parts I always seem to drop in there. Thanks for sharing! I look forward to your next posts!