Just to add a bit.
I hope you find the recommended tech and that they are of great assistance!
Other than that, most any older(Sorry about the "older", but it's gotta' be true), retired even, radio/TV station or recording studio engineer might help with the basic alignment and inspection/checkout of the machine(And maybe just "for fun"? You might even wangle an invite to a stations engineering shop - where the test gear is..?). Worth a try calling around and asking for the chief or maintenence engineer? Most of these guys are very cool and very generous with their knowledge - I spent most of my time at stations in their offices, even though I was an "other side of the glasser". Unfortunately, these days, if you try too small a station they won't have a full-time engineer and too big a station, you may not get through to them(Be extra-sweet to the telephone answering person!). Worth a try though... On further reflection, make sure to try local recording studios - those that have been around for quite awhile. I know that a long-time friend of mine still has her 30 year-old 8-track in some room, somewhere, for instance and she'd still be able to align it blindfolded!
But the "service" part - maybe especially for an old Tascam or Teac..?The biggest problem I foresee is that any needed parts, even pinch rollers or whatever, may be v-e-r-y hard to find, anywhere? Or not! What with the web seeming to provide everything somewhere? I hope you also got the manuals(Operating/service) with it? If not, they may be available on the web, too, for free or low-priced download.
BTW: With the manuals and a little patience/study from any number of sources(Old audio recording manuals at the library, used book stores?), you may be able to accomplish many tasks yourself! If you're going to "go analog" you'd better get used to maintenence or hire your own "chief" - maybe out of retirement...
Best success! Sounds like a fun gadget!
TG