David,
Hi. This link
http://ca.skywatcher.com/upfiles/en_...1316546656.pdf shows how the Synscan is installed into the Heq5. The control panel has two cables on it which is threaded into that tiny hole. To access it, via these instructions, looks like removing the side cover and then the upper cover to get access to the other end of the cables. I will try this with my mount and see how hard it is to remove the control panel - while I have it out, I will work out its schematic, then put it back.
-John