Description

This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.

09.012 In connecting a second Disk II drive to my Disk II card I misaligned the connectors. The result upon turning it on was a static-like clicking noise. Now I can't load anything from disk. Is the Disk II card dead? Are the IIe and Drives all right?

         Try removing the drive which was connected incorrectly. If your system
boots from the remaining drive (connected in the Drive One position), this is a
fairly good indication that the Disk II card and IIe are okay and that the
removed drive is messed up.

     If it looks like a drive is bad, remove the cover and inspect the drive's
main circuit board for blown components. If nothing obvious shows up, a decent
fix try is to replace the 74LS125 IC on the drive's main circuit board. (Also,
see Q&A 013.)

----------------------------

By:  Ryan Underwood

     I accidentally offset a row of pins on the //e disk controller card when
plugging one of the drives in. Snap, crackle... you get the picture. I opened
up my freshly fried Disk II, and in the center of the board there is a 74LS125
that is blown. Replaced it (it was socketed) with the same chip from another
Disk II, and voila! it works again.

     I would reasonably assume that misaligning the drive connector on the
controller is what blew the 74LS125 in several Apple II drives before they got
to me. Note that while the genuine Apple Disk II simply lights the LED and
doesn't move the head at all when this IC was blown, a Mitac drive actually ate
disks. So any number of dead Apple II drives with different symptoms could have
a blown 74LS125.

___________________________

By:  Rubywand
    

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