trying to make the tape deck work. started taking it apart and learning what i can from youtube etc... i replaced the belt and adjusted the motor speed but still get a whining noise when a tapes played. not sure what the next step is or if i did something wrong. looking for some direction.    

Use a contact cleaning spray on the record arm. It will be a long switch type lever on the main board beneath the deck. Clean that with spray and work it a couple of dozen times, see if that relieves the noise.

try cleaning the heads and the capstan/ pinch rollers. It's a an easy point to work from. Good luck and keep us posted.