as far as I can tell, only one episode is edited. Every episode runs 25 minutes but one runs 21 minutes. The shortened episode is 'Fonzie's New Friend' and, even though I dont know the episodes inside and out like some people might, I did notice one huge edit and was wondering what was taken out of said episode.
It is the scene at Arnold's drive-in when Fonzie introduces the new drummer for Richie's band. At the end of the scene Ralph Malph says "I love watermelon" and then the cut QUICKLY jumps to Richie in mid-hysterics talking to Fonzie in the restroom. So what was taken out? It's pretty obvious something was taken out. What else is missing from that episode?
Again, every episode runs 25 minutes except for this one. It's too bad this is not mentioned on the back of the DVD cover(the music issue is, but not the film edits).