Why does tape go slow, then stops?

I would not think of a solenoid over heating but as the tape proceeds the torque on the reel change due to the change in diameter of the radial arm of the tape. The problem is more likely a stretch capstan belt that is slipping, shiny capstan shaft loosing grip, dried bearings that need oil and are heating up. It could also be related to a non compliant pinch roller- it would be shiny and hard. Any or many of these things can cause the speed issue- The deck of this age need a Technician to go over it. I am a past Teac Technician and have worked on many of these decks. I operate Skywae Tape deck repair in the Chicago area.

Gary hi! I am not sure whether your machine is solenoid controlled but if it is then I would suspect the solenoid that operate the capstan roller to be overheating, I had the very same problem with my Studer and Revoxes and when I smeared some heat sink compound (Available from electronic stores selling components like Radio Shack etc.) and fit if the chassis is cast aluminium like the better manufacturers use,as a heat sink. You can chech the belts and the lubrication of the drive system but I doubt that. Clean the capstan roller with denatured alcohol or cleaning alcohol.