Hi Dave, I don't know of any specific tune up for the DW788, but I can help you out with your tension problem. I had the same issue, you can read about it here,
DW788 Woes and also find the solution. It was a very cheap fix, as you'll find reading through the attached post.
I also have problems lifting the arm, but I've never found a cure for that problem.
Rick Hutchinson has a very good site and can answer alot of guestions regarding the DW788.
Hope this helps, and welcome to the forum
Marsha