By this point in time, I'm sure you've already heard this a bajillion times, so here are the pertinent details:
0) I know, backup, backup, backup. That's the problem. This WAS the backup.
1) Goddamn Tornado series.
2) Platters/spindle seem fine. No abnormal noises.
3) Tried the freezer trick, since it was making clicking noises at first, like a stuck spindle. Problem now attributed to the external enclosure's board being the culprit. Deduced by hooking it up to my trusty USB-to-SATA/IDE adapter, where it would spin up and sound healthy.
4) Goddamn Tornado.
5) Was able to read files for a little bit at first, but again, only about 32 cylinders' worth at a time, then spin-up loop.
6) Reads to 32 cylinders, then stops, and re-spins-up.
7) No, I don't have another PCB to act as a donor board.

Tried the eraser/Brasso trick on the board's contacts. No dice.
9) Failing a donor PCB, who to contact for data recovery? OnTrack still good?
10) Did I mention, Goddamn Tornado?
11) No camera on-hand to take photo of the foam/PCB right this moment. Photo is forthcoming, but the foam is pretty "dirty"? "burnt"? PCB is scorchmark-free, thank prime.
Any help, from reprogramming the board, to a donor PCB would be appreciated.