Kennedy 96xx takeup arm

I don't *think* this is OT, I don't see any IC date codes newer than '89... Is anyone here familiar with the inner workings of a Kennedy 9662 tape drive? FWIW, I think the 9610/9612/9660/9662 are all essentially the same drive, depending on the combination of {rack mount vs. table top} and {Pertec vs. SCSI}. My problem is, the drive keeps giving "TAK ARM?" errors, which according to the manual, means there's some problem with the takeup arm (i.e. the motor-driven arm which has the takeup pulley on it). I've been all through the manual section on how to adjust the various relevant sensors and I *think* I've got it more or less happy. I fiddled with the height of the capacitive disk thingy (which evidently is what encodes the arm position for the on-board micro), it was way off but now I'm getting more or less the voltage spread that the manual asks for and the "zero" position does give 0.0V. But I'm totally stuck with what to do next, partly because there are some differences between my drive and what's in the manual. The manual claims that there's a mechanical limit adjustment, but there's nothing in the area where the arrow points (it's not even visible on their sketch so I don't know what they mean here). The cam that drives the micro switch to set the limit of arm travel is nothing like what's in the book, I've been dinking with its set screw trying to move the limit one way or the other but the same mechanism seems to be what drives the *actual* mechanical limit (there's one peg which pushes another) and I don't seem to have independent control over them -- maybe that's on purpose since the manual wants the switch limit set a fixed angle past the mechanical limit (I would think they'd want it the other way around though???). Anyway I have no idea what to do next, is this familiar territory for any of you folks? FWIW the drive gave the same message when I first got it, but after I randomly poked and prodded around the takeup arm a bit it magically started working. So of course I'm suspicious that the actual problem is just a flakey connector or something (I've wiggled them all again) and not the mechanical adjustment at all, although as I say the range that the encoder was giving was all wrong. Unless it's actually my manual that's all wrong. I'd really like to bring this thing back to live, it was a wonderful tape drive. Thanks, John Wilson D Bit