6128+ disk drive manuel ???

[Bryce]

Alps devices seem to all have a very similar PCB (judging by the pics I could find online). So yours probably looks something like this: http://www.pitsch.de/stuff/amiga/alpsdf354h127f.jpg
If so, then add a solder blob to the two pads on the righthand side of the "RD" as seen here. That should be enough to fix the problem. If not, add a wire from this blob to pin 2 of the header connector.

Bryce.