I just had some similar issues with my TZ. My game would reset after a couple of minutes at any time possible. DMD issues, sound, speech, coils, everything. This would happen during Diagnostics, while playing, attract mode, etc.

I am far from an authority on these issues. It was recommended for me to use rubbing alcohol and a toothbrush. I cleaned all of the ribbon connectors and all of the male connections on the boards as well. Then while still having alcohol in the connections, I seated and reseated multiple times to get everything nice and clean. Then I let the alcohol dry and evaporate before putting it all back together.

Holy shit! Works great! I hope that I didn't just jinx myself.

Edit: To be clear I didn't clean all male connections but only the ribbon cable ones.

I'm curious if anyone has any thoughts on the rubbing alcohol solution. I was leery about it and am so impressed about how well it worked. Jim used the same terminology as the op by saying that my game was confused and that the ribbon cables were not communicating correctly from board to board. He used a southern word that I cannot recall but basically said that all the "crap" needs to be cleaned off in order to get a good connection again.

A big thanks to Jim at Rottendog for picking up the phone and sharing his knowledge and tech support. I hope this works for the op as well if he tries this solution.

The rubbing alcohol fix is still working for me over 3 weeks later. The only difference is that my attract sound went from the TZ sound to the Jackpot sound. I can live with that unless someone has a suggestion to fix.