Thanks for the response. Roger on the 290 degrees. I was using applewood chunks. I was rolling along at around 280 and went to get an adult beverage. When I returned my temp had shot up to 400. Enough time had gone by that the ribs were pretty charred at that point, only an hour or so into the cook. I couldn't recover from there - the damage had been done.
I ran a test the day before (without cooking any meat) to make sure I knew how to control the temp. That went well - I was holding at 280 for several hours ok. But then dumb me changed the basics by adding the apple chunks on coo