Amlyn cartridge drives

Once you find the track, then you can read easily. The track is pretty normal. But the track positioning is 170TPI! (in its native mode). It can also do 48,96,100 TPI, and could probably, with no real effort, read disks with defective radial alignment! You could: modify the stepper mechanism/radial alignment of a conventional drive, to manually find the tracks. OR hook up a scope, and just start shoving the head back and forth with a finger until you find a track. On my 1990s TUIT list was: "add a micrometer spindle to the stepper of a drive to be able to offset alignment". Take a look at "Computer Technology Review" Winter 1983, "Closed-Loop Positioning Method Raises Capacity Of 5.25" Floppy Disks" By Richard E. Johnson of Amlyn also: [borrowed from an outgoing FPUIB cart]: "AMLYN 1500 SERIES\nHIGH CAPACITY FLOPPY DISK DRIVVES\nPRODUCT DESCRIPTION\n\n The Amlyn 1500 Serieds Flexible Disk Drives are a family of new generation flexible disk products from Amlyn Corporation. The Models 1550 and 1560 offer 1.66 and 3.32 megabytes respectively of unformatted capacity with 95milliseconds average access time and 500 kilobits per second data transfer rate; the highest capacity and performance . . . Amlyn Corporation has taken flexible disk technology into the next generation . . . 9500 bits per inch and 170 tracks per inch to achieve the highest . . . To facilitat ease of system integration, The Amlyn 1500 Series utilizes the industry standard SA460 electrical interface, track format and 8" data transfer rate to minimize system modification . . . . . . enabling easy database conversions and the use of existing . . . 48, 96, and 100 TPI 5 1/4" diskettes. CLOSED LOOP SERVO To reliably achieve a track density of 170 tracks per inch, the Amlyn 1500 Series employs a closed loop servo . . . The basic elements of the system are a reference track on each diskette, optical scale located on the head carriage, high speed precision 1.8 degree stepper motor and microcomputer control. The reference track . . . serves as the point from which all data tracks are located and is also used for analysis of, and subsequent compensation for, anisotrophic growth of the diskette substrate . . . Microcomputer control ... 59 microinches"