The high capacity drives (> 40 MB) usually don't use stepping motors to position the heads. They use "voice coil" technology. A coil of wire is attached to the rear side of the disk head positioning arm. The field created by this coil acts against a pair of nearby magnets. The position of the head and coil is proportional to the current flowing through the coil.
The good stuff to salvage from these drives is a pair of really powerful magnets inside the drive case. You have to remove a bunch of really wierd security screws to get inside the drive enclosure. IT is worth the effort to get these really powerful magnets.
Thanks for the HP 7475 driver leads... I will check them out and report. |