These are notorious for not working and this is the first one I've ever seen or worked on...but ya know I got it working...
At first the pass-thru connectors weren't working to read the carts but after a lot of screw tightening and cleaning...that worked...
...then it was on to the Jaguar CD itself. We didn't have any CD games to test it with so I stuck in a CD...didn't work...but after I took it all apart, cleaned it, tightened it to where it was sitting balanced on the Jaguar (the main issue these things have) *and* properly placed the closing trigger (which was just a flimsy plastic piece sitting on a leaf switch) it was spinning music CD's and playing them. Came back the next day with some games I burned to see if it'd play CD games and yes, I fixed it...worked like a dream.
Took this glamor shot of it working with all our Jaguar games and the official cords and this was instantly bought by a collector the day we posted about it.