Altec/ Lansing TMB 156...

so is it an input or output? Step-up or Step-down? how do i test for this? or are all transformers interchangeable? lol, which i know there not, guess ill have to run audio through it and see what happens? from the schematic painted on the top of the transformed it looks like it is an output since it has leads: 1+2, 6+7 on one side of the iron + leads 3-4-5 + 8-9-10 on thee other side — these center tapped leads "4"+ "9" (are the center taps) look like what you see on an input transformer, but wouldn't they be labeled/numbered "1"+"2" / "6"+"7".. someone help please : . —±2πø∞