ARR-7  HELP Needed motor Thingus and etc to make work for ARR-7  hf rx.  Seems people pulled the  motor thing off the front. Help?.

Need to understand why e em though there is a dumimg knob this was removed?  Seems to be a hf scanning countermeasures receiver. Would like to restore back  to orig

. Do not have orig p.s.   have a 3ed party one..  thanks Ed Sharpe  archivist for  SMECC