When you great grandpa was your age and hard drives were the size of cereal boxes to operate them HD controllers had to manipulate position of disk heads directly. Not like these lazy modern controllers that only request data and hard drives are just operating themselves. So yes, when controller of such ancient drive went to The Land Of Eternal Seeking and there is no schematics at hand you are pretty much left with one simple but hardcore solution https://www.youtube.com/watch?v=SwEi7dK3rIA