However, this lever had other things on its mind. I was confident I'd come into the shop the next day and it would be working like a champ. Wrong! Still wasn't working. Hmmm, wonder if Shimano is wrong about the internals not being serviceable. A fifteen minute google search yielded this site on 9-speed STI shifter overhaul. Pretty exhaustive work by the author and very handy.
With this newly found info in hand, I tore into the shifter. Now, it's always pretty easy to take something apart. Putting it back together, on the other hand, well, not always so easy. In the case of the STI shifter, it's a major pain to get the springs to cooperate. I made a tool out of a small screwdriver - basically, cut a slot on the tip of a flat blade screwdriver that I could use to coerce a spring back into it's hole.
The tool's a keeper. The shifter is not. When the shifter was disassembled, I noticed the same problem that was noted on the overhaul site - namely, that the ratchet pawl cage was damaged as shown in this photo (lower right corner).
So, I knocked off the burrs on the damaged section and set about to reassemble the shifter. Hey, maybe by cleaning up the burrs, it'll work. Nope. Got the shifter reassembled and still no go. Next time a non-functioning road STI shifter comes in, "sorry, those aren't serviceable." Lesson learned.
(What's playing: KWMR)