Obviously it sounds like an issue with the smoke unit. I would pull the top and make sure, for starters, that there isn't a smoke fluid overflow that is potentially causing some sort of short when the smoke unit is activated. Smoke fluid is oil, and oil drenching, for example, an electronic board could cause issues. Use a lint free cloth to gently dab off any overflow. If you see fluid on anything electronic, I would use a bit of compressed air (air in a can) to try to clean it off. Perhaps give it time to all dry out and then see how it does.
If still no dice, my sense would be you probably need a new smoke unit. But proceed step at a time.
