some work,, some don't

I just bought a BDP-s1 second hand. Cosmetically speaking , it looks brand new, yet I have no idea of the "play time" it has had. I have attempted a couple of Blue Ray videos from Red Box and neither has worked. I also have played some of my own Blue Rays and they have worked, however a couple of my own did not work. I did not pay a lot for this unit but I thought I was getting a very high end product. Is there any hope for making this unit work with consistency or is it just an outdated? I would appreciate any help Thanks Brian