Sure sounds like it's not getting enough power I would try removing the DMD and other high power draws and see if the game plays better and then Troubleshoot from there - also check the chip right under where the batteries are reseat that and lastly a large plug for the power try reseating that as well.

negative I can just say I had a whitestar game do this, and it was either chip under the battery or the power going into the I/O board - one or both of these had issues and I had a delayed start - and slow response time. The response time was because of a switch matrix issue so it took a long time for any switch to work as it triggered all sorts of stuff.