I wondered if distance would be a factor, but in the example on Brilldea's website they have a pretty significant length of ribbon cable between each painter. And if length of cable was an issue, I would think that the first painter board would at least function correctly, right? In any case, how would I go about buffering those signals?
On the bright side, I was just looking through those pictures I posted, and I noticed that Painter 3 was plugged in wrong. The ribbon cable was plugged into the OUT side instead of the IN side. I corrected that and all of the lights are bright now, but they're still displaying randomly.
I think I can rule out issues with the power supply, now. I'm going to try swapping out some of the chips later today, to see if that's the problem.
Oh, and I did change NUM_TLCS to 9 in tlc_config.h. I'm using Arduino in Ubuntu nowadays, though. Maybe I'll try it out in Windows just to be safe.
Thanks for the response, Mike. I know I wrote a lot, but it helps me to figure things out.