This is my first time at using the mechanism after receiving it, it is second hand but looks in good order. There are already cd covers in the plastic envelopes already, I will check if any maybe making it jam. It only seems to jam when moving certain pages, this type slides the page from side to side, it does not flip over like a book. The edge of the page sides sometime catch when the mechanism tries to slide it, I wondered about filing along the edge to make it more tapered, so it will slide over the page next to it, instead of catching into it.