I was distracted, forgive me, Extra it is Extremely poor centering, which could also be a dirty pot, jerky linkage motion indicating broken gears, stuck output shaft, "hunting" for center, are all indications for a worn out servo. Typically the 148's would break a gear during an impact before they actually wore out, and when they wore out they simply stopped moving in the last position they were in.

A truly great product in it's time. Airtronics had a servo of similar quality during the same period.