Aligning The Heads On A Five And A Quarter Inch Floppy Drive
| Field | Electronics |
| Went Obsolete | 1990 |
| Made Obsolete By | Improved storage media, cheap replacement drives |
| Knowledge Assumed | Basic electronics |
| When useful | Repairing older/obsolete equipment |
With many of the 5.25” disk drives available in the early 1980s, problems could arise due to misalignment of the read/write heads. The popular Commodore VIC-1541 drive was especially prone to head alignment problems, sometimes needing realignment as often as every two weeks. Computer repair technicians were thus trained to realign the heads, and even hobbyists learned the skill to repair their own drives.
To align the heads on a 5.25” floppy drive, you needed an alignment disk. This was usually found at your local computer dealer. Then you ran a diagnostics program that would usually step the heads manually from track 0 to the end track of the disk. A simple 10 Mhz oscilloscope was then connected up to a test point located on a circuit board inside of the drive. Usually, one would see a sinusoidal waveform on an oscilloscope. Then they would loosen two screws holding the stepper motor in place and gently move the stepper motor up or down until you saw a peak voltage on the oscilloscope. Afterwards, the screws would be tightened slowly, one at a time, while carefully watching to ensure that the heads didn't go back out of alignment after tightening the screws. Then you would step the track motor and hope that the heads remained in alignment.
Improved mechanics and lower prices soon made this skill unnecessary, though, as drives became less expensive and more reliable. Soon it was cheaper to replace the entire drive than to spend time repairing it.
(NOTE: Though this skill may not be common, it was for a short time a respected technical skill and may safely be considered rendered obsolete by modern storage media.)
