Someone suggested cleaning the tape coating the inner rim of the platter with alcohol. I am not sure this is a bad idea, but it might be. The guiding principle is that that tape coating is essential to proper function of the speed control system. If you scratch or break the tape, the turntable is probably toast, as someone else did say. So, I would first inspect that coating. If it’s filthy, you might try to clean it with something gentle. Also, as someone else said, the tapehead-like thing that reads the tape may be loose. But I do not know per se how that could lead to the platter running in reverse. These decks use a single integrated circuit that controls speed based on input from that tape head. The IC may have been damaged.