Apple Preserves 5.25" Sync Sensor

A precision Hall-effect track sync sensor for the Apple Preserves FDC, designed to fit the Apple 5.25" drive. The sync sensor anchors each track's start to within about 1 µs, so flux captures can slip by at most a single bit cell — the foundation the FDC's copy-protection analysis is built on.

This version is laid out specifically for the UniDisk 5.25", with the audio jack positioned to route the flat 3.5mm cable cleanly inside that drive. With the wide variety of Apple and third-party 5.25" drives out there, cable routing differs from drive to drive — this is the one to choose for the UniDisk 5.25".

Includes a precision neodymium magnet that glues to the edge of the drive's large center spindle. The sensor reads the magnet once per revolution, giving the FDC a precise track-start reference.

Built-in test mode: a USB-C port and onboard LED let you verify the sensor without any other hardware. Just apply USB power and pass the magnet by the sensor tip — the LED lights on each pass, giving you instant confirmation that the sensor and magnet are aligned before you finish the install.

Works with the Apple Preserves FDC. The FDC supports two drives and two sync sensors — buy a second sensor to image from two drives, or as a spare.