Trossen Robotics has come through! Just received my replacement eb500, which they kindly tested before shipping. Plug and play! Worked instantly out of the box with Papywizard on Nokia N800!! The Skywatcher/Merlin follows all commands perfectly moving the head in all directions and with pre-sets. I will send defective eb500 back to Trossen and they indicated they would test the board and report back to me with the cause of failure if they can detect why.
I received my replacement module today...still no luck. Same issue. I'll call tomorrow and see if I can get a clear answer if the original was deffective or they just sent a new one? Either way ...annoyed.