There is a certain amount of "set up" required when you change a cartridge, however its not too difficult and you will find turntable and arm manuals to download for free at the two sites I emailed you the other day, which explain just whats involved.

The Shure M75 mm cartridge that is in the arm at the moment can just have its stylus replaced. If you remove the headshell and grip it and pull the cream section of the cartridge you will find it pulls out ( pull slightly down and away from the cartridge body.)

Genuine Shure stylii are quite dificult to come by, and copies are also a bit thin on the ground. It calls for a bit of research on t`internet, which is something I was going to do myself but never got round too.

Each stylus is usually bespoke to that particular cartridge, its not a one size fits all solution...... sorry.