hello all,i got a old reel to reel(penncrest 6433) from my brother&i could use some help.first thing i need help with is how do i get the play,fast forward,rewind knob off?i tried pulling up on it,prying gently up on it,didn't move any!don't want to pry to hard cause of plastic.i was able to see under the faceplate that the belt was broken.thats my second question,where can i get a belt for this?thanks in advance for any help.