Well, I figured it out… the switches checked out OK and I reflowed the pads, and when that didn’t help I started probing for continuity. I saw there should have been a signal getting from C1 to R2, and on looking closer the trace looked a little funny – turns out that was because it isn’t there:

So I tacked a wire on there, and sure enough, the OD works just fine. If nothing else I’m glad it turns out I put it together correctly, lol.