The CPU, also at this point, automatically turns on the reel motor to complete the process. In addition to the above, all moving mechanisms control the tension arm. When unloaded, it's behind the left roller guide. As the tape loads, the roller guide gets out of the way and the spring tension on the arm puts it in the correct position without any other help. But on the unload part, something needs to pull it back slightly so the roller guide can catch it and pull it back in.
Most moving mechanisms have a cam on a slide bar that does just that.
This is pretty much in a nutshell what the moving mechanism is, what it does and how it works. If you can understand this page, you have grasped the basic concept of VCR mechanical operation. From a troubleshooting standpoint, it's an excellent advantage to understand how this works. If something is not doing what it's supposed to, you now have the basic knowledge to figure it out. Submit a tip.