Eric Schlaepfer's "Floppy Drive Exerciser" Is Everything You Need for Fine-Grain Disk Control
Handy board breaks out every important signal from a vast variety of drive types, from Shugart 8" to standard IBM-style 34-pin.
Eric "Tube Time" Schlaepfer has built a circuit for those who have a classic mechanical floppy disk drive that's getting a little old and tired, in order to get it back up to speed again: the Floppy Drive Exerciser.
"New project release! this one is a floppy drive exerciser board, good for testing and aligning all sorts of floppy drives," Schlaepfer writes of his creation. "The board basically breaks out every signal to a control switch, indicator LED, or test point. It's not designed as a flux imaging tool — it's just a simple way to exercise features of a floppy drive."
If you're wondering whether Schlaepfer's creation will work with your particular floppy drive, the answer is almost certainly yes — unless you've got something pretty rare on your hands. The board includes connectors for and compatibility with the standard 34-pin IBM-style 3.5" and 5.25" drives, IBM's unique 40-pin PS/2 drives with their embedded power connections, classic Shugart 8" drives, the Apple Disk II, Hewlett-Packard 34-pin and Sony 26-pin drives, and IBM 31SD and 51TD drives.
Aside from the plethora of drive connections, the board features satisfyingly clunky toggle switches and tactile buttons, a pair of potentiometers for controlling step pulse width and step period, and a section Schlaepfer describes as "optional," which uses a rotary encoder and a two-digit seven-segment display to allow for manual track selection with automatic stepping.
As Schlaepfer says, the device isn't designed to interface a vintage storage device with a modern PC — and can't easily be used to image the contents of a disk, as with an Adafruit Floppsy or similar. It does, however, provide extremely fine-grained control — ideal for testing, aligning, or experimenting with various drives, and even including half-track, double-track, and 1.5x-tracking modes, which Schlaepfer says is "useful for getting 32 tpi [tracks per inch] from a 48 tpi drive."
Design files and source code for the board are available on GitHub under the reciprocal Creative Commons Attribution-ShareAlike 4.0 International license.