I agree with cavey, especially in your circumstances with having head replaced, you already have been stuffed around a lot. They should be coming to you.
I wonder if in replacing the head that it missed some critical checks that normally would be isolated at the factory or a wire or plug has been located in correctly.
Did stern replace the head box only and all the boards moved from one box to another by AMD?
As for others further away we need to return the item to them, keeps their cost down which is a another reason why they should have a registered tech in each state at least if not other distributors.
