!! XF551 Indexlochabfrage - Indexhole Detection Upgrade

The Atari XF551 disk drive was the first to use an industry standard drive mechanism which was capable of true double sided operation. However, many 1050 owners use the back sides of their disks by simply flipping the disk over and notching a write protect hole. Since the XF551 uses the index hole on the disk, flipping a disk over and formatting it is not possible. In 1991 German company EDV Computer Shop created the Indexlochabfrage D-503. This small PCB could be built into the drive mechanism and simulates the detection of the indexhole. As a result XF551 owners could flip the disk and write to it just like the 1050 and 810 drives.

[XF551 Indexlochabfrage - Indexhole Detection upgrade/Indexlochabfrage1.JPG]\\
[XF551 Indexlochabfrage - Indexhole Detection upgrade/Indexlochabfrage2.JPG]

Including schematics\\