Welcome to the Club! The best-known places to fix/re-calibrate TOTL Nak decks are: ESLabs Willy Hermann Theoretically, you can get a set of belts from MarrsCommunications but to properly calibrate The Dragon you will need pull- and back-tension cassettes, mirror cassette, certified test-tones cassettes just for the mechanics. Very expensive nowadays, but normally unobtanium You may also ask folks at our sister site Tapeheads because ESLabs and WillyHermann sometimes have a back-log for months and months
That's a great deck that still has a lot of interest. The repair shops are really fading away but there's still a bunch of one man operations out there, if you can't get a good lead time from the big guys. I would try calling around to electronic repair for musicians and pick their brain. When you get some leads ask about the equipment Jorge mentioned, if they don't have tension or tone cassettes find another. I don't know, but I have to believe there's a guy in Jersey that knows the machines inside and out. My personal experince is these guys are pretty old, have an old-school shop with all of the test equipment but they do very little advertising and really don't care about marketing their business since they're in the twilight years. Make sure you label all of your equipment in case something bad does happen, if the doors close you may not get it back.
Sorry, I thought you meant our Jersey..... The owner of the forum might be able to help, he's Walkman Archive and he has some really nice equipment or ToolCool4, he might have some insight.