TRACK ZERO SENSOR WARNING !


Floppy drives have an sensor to detect track zero position which tells the drive the positioning of the first track on the disk(hence all tracks). On some drives it is mounted on the same PCB as the capacitors and removing the PCB will dislocate the adjustment for track 0. If the screw holes for the PCB are elongated (thus allowing for adjustment) then there is a good possibility the track zero sensor is on the PCB.
One way to determine bad track zero adjustment is by formatting a disk on that device. It will manage to read and write a disk formatted by itself, trying to read a disk written on another known good drive will fail because the track offsets differ.

Adjustment of the zero stop should be done using proper equipment and not by trial and error.

.. in other words, (TL;DR) do not touch the track zero sensor adjustment 🙂

 
 

BAD CAPACITOR SYMPTOMS

Assuming there are no mechanical faults, the symptoms are intermittent failures/halts or read errors, buzzing noise when moving R/W head (motor not able to move properly) or even totally dead.

Some drives allow for capacitors to be relocated to the other side of the PCB which might provide a better environment and space for capacitors with better specifications.
 
Before continuing, make sure to read the warning about TRACK ZERO SENSOR above.