Using Sitech 1 in place of Celestron Nexstar 8i controller?

My Azimuth motor on NexStar 8i runs slowly occasionally and it is a controller problem, as no drag on bearings, etc., and putting pressure on scope doesn't speed it up. It does find and track OK, but SLOW slewing sometimes.
I note that Pittman Servo Motors are installed and it seems a simple thing to just rewire and run on the Sitech 1 with my Argo Navis instead of the Celestron Handset.
Has anyone tried, or done that?
Or suggestions on where problem is for Azimuth Driver System.
Thanks - Mike