I got my model 15 cleaned up and lubed save grease on big gears (im trying to stay as clean as possible tweaking it) The question I have is this I tested the base alone after doing some minor repairs and the motor works fine...I hooked up the printer to the base and free handed it...  I dont have my DC supply yet I just bought a Hal 5000 so that will be my loop and how I get ITTY....  I can go one revolution and the unit stops whem a pawl on the left side of the machine engages... I cant seem to find its name on my diagrams nor can I understand why it's engaging... I thought that the unit could run on AC and would just chatter... I was thinking this would be a good way to ensure the main drive train is good to go...  Ive attached a pic..