Teac FD-55B Floppy Oddity

My Otronas have FD-55B-01-U drives in them. I thought the drives were fried, since they wouldn't work on the Otrona nor on the PC, but in dinking around, I determined that on at least one drive (and probably the other), the head load solenoid is not pulling in. I see power being applied, but it only looks like +5V. I don't have schematics, and I'm not ready to risk wrecking the drives determining the following question: Should the solenoids pull in on +5 or +12? If I'm seeing +5, I suspect the solenoid driver transistor could be cooked. The solenoid coil is intact, as I'm seeing 44 ohms across it, out of circuit. In either case, I don't feel even the lightest twitch when it's supposed to pull in (and the jumper is in place, for load on motor select). Does anyone have any FD-55B (these are the 360K DS-DD 48 TPI) drives they'd like to part with, either to see an Otrona running, or in exchange for ye olde green stuffe? --John