Alright, time for the happy ending
This all came together between yesterday and today. I was eagerly awaiting my
overnighted package consisting of a capstan belt and a solenoid gasket (which Teac decided to screw up shipping on and send it back to themselves, in which I very strongly suggested to them that they now overnight my package because they promised me "by the end of the week"), and on a whim last night I took the advise of DuddyGuy after he posted a local-to-me listing of an M-308 in my other thread about the Teac 5. I ran up there after work, picked it up and brought it home. The thing is in pretty much mint shape, and I'm really glad I grabbed this.
This morning I got up at the crack of dawn and took the 38 apart and installed the new belt, replaced the gasket around the braking solenoid (that was pretty annoying BTW, the gasket doesn't stick to anything so I glued it to the c-clip just so it wouldn't interfere with the solenoid pin, which was also pretty gummed up from old gasket goo). There is still the other solenoid at the top that has a nasty gasket so I will have to fix that one eventually too. I then blew a fuse while pulling a vu meter out enough to have access to it (stupid me left the machine on). Replaced the fuse, got the one VU bulb working again. I then replaced
all the VU bulbs (courtesy of Parts Express, thanks GCalo!) and tested good. I also went underneath and reseated the 8th card, but haven't tested it yet (it wasn't passing signal). I apparently lost the little plastic washer from inside the pinch roller because it wasn't spinning free when I tightened the cap. I made a temporary one out of thin plastic just to get by. I then cleaned the pinch roller with CaiKleen RBR (by Caig) which rejuvenates the rubber. I cleaned the heads thoroughly, demagnetized all the metal parts including the heads, rotated the right tape guide, and turned it all back on.
I have an old tape which came with the unit, and I decided to give it a shot and see if anything played on it. Sure enough, there were tracks on it and I was able to hear two of them (don't have enough cables yet) through the M-308 so it does work! The tape is nasty so I don't plan to keep messing around with it. I bought a new reel of RMG 911 for when I'm ready to try some of my own recording. I tried to run an instrument through the M-308 into track 1 of the 38 and record it, and I got VU activity, but it would not play back. I either have it wired wrong for playback (into tape-inputs on the rear of 308) or I have the mode on the 38 wrong. All I know is it plays in sync mode, nothing in Input mode, and what sounds like a smtpe time code or something in repro mode...? Still have to mess around, but I'm super excited!