That ISE 77 looks like the one that was in my house when I moved in.Start cap removed and rotor locked up tight.When my plumbing was replaced last year the old ISE went out in the plumbing scrap-all of the cast iron drain pipes replaced with PVC.A new Moen half hp disposer installed.has the PM motor.Does work OK for what I need.So I put the really old VitaMix blender I used as a "disposer" under the sink just in case it was needed again.My house was built in 1972.That could give an idea how old that disposer is.