Sorry to necro a thread and all but I wanted to post back on this since we JUST fixed this problem tonight, and someone might find this thread via Google.

One of the vertical deflection yoke wires was broken. No idea how it happened, I'm guessing it was just from age. We resoldered that single wire back together very carefully, and it worked perfectly.

We used a technical reference for the Classic II's CRT to figure out that it was the broken wire in the yoke winding.

Reference here: ftp://ftp.apple.asimov.net/pub/apple_II/documentation/macintosh/Classic%20Mac%20Repair%20Notes%20.pdf