Are you trying a copied map disk or an original? If a copy then get or borrow an original to test. It sounds more like you have a laser problem than a drive problem. There appear to be an 8 pin laser for all but the newest MK3s and a 10 pin laser for the newest MK3, 65 90 6 922 720. I have one of those which has the 23F number. It is my spare back up nav for my MK4. It is a very good unit and I suspect a little faster than the earlier MK3s. I think all the earlier MK3s had numbers, on the label, prior to 23F which would be the 8 pin laser. My dead MK3 has a 23B number. I know you can find both lasers at at least 2 places on line.