Ok, definitely not a 1:1 TMS1xxx clone then. (or did I already say that before?)

Coleco Amaze-A-Tron is running fine in MESS. You really need a board+playing pieces to play though. I fixed 1 bad bit before writing the driver: amazeatronraw.bin offset $596, change $1A to $9A.

Right now I'm tinkering with MP3403. We're in luck: it has a 1-bit speaker on R9 and plays short jingles when I press random buttons. My 1st guess is a horse racing game.