Atari 1050 Floppy Disk Drive Tested working / with Mod / drive only with owners guide.  No cables, No power supply.  Drive only.  With disk, it boots to dos.  Then we looked at directory.  Then we read a text file.  We don't know which mod it has, but it is nicely done.  When booting with green light, it goes to dos from disk being used.  When the green light is off, it bypasses and our atari 130xe went to basic normal screen.