I feel your pain Mike. It has now been months since I have had a fully working camera on the Newtonian. I had two new QSI's which had issues with the filter wheels, both have been returned and I have now gone for a refund and purchase of an Aluma 694 with integrated filter wheel. At the same time my QSI683 was in for repair twice and I am expecting it back today from a 2 month repair after a 6 week repair the first time. This all meant a stop start approach to imaging. I don't like problem solving I just want to image!
You experience sounds a lot worse, but it is good to hear you are getting to the point of imaging again.
Greg, I thought I read that the ST-i is now discontinued on the Diffraction Limited website.