Quoted from TeaHaus:Gotemwill's detailed instructions are exact. The only thing I would add is that if this is like my 1965 Bank-a-ball, there is an additional lock inside the cabinet that you have to pull toward you as you lift up on the playfield. It's a big brass bar that spans the width of the playfield............
My Gottlieb King of Diamonds (1967) has that odd playfield lock down bar just like you mentioned.