Re: Adding a second floppy drive to an Apple IIe

[Linards Ticmanis <ticmanis@gmx.de>]

On 05/05/2011 09:58 AM, Michael J. Mahon wrote:

> Dave is right, a blown 74LS125 will disable the read channel (among
> other things), and a drive that turns on and seeks, then just spins
> (with a good bootable disk) is a sign of no read signal.

Especially if the drive "eats" disks (meaning it doesn't boot, and any
disk tried in it, even if it was write protected, won't even boot on any
other drive any more), the 74LS125 is the culprit with a close to 100%
chance.

So be certain not to insert any disks with valuable content into the
drive unless you have first excluded this failure mode (I found out the
hard way by losing an original game disk this way). The disks won't be
physically damaged, after the drive is repaired they can be re-formatted
without any problems, but their former content will be gone for good.

If it isn't the 74LS125, the ULA 2003 might be damaged, but that is far
less likely. I've yet to see a drive in which any of the other two chips
has failed.

-- 
Linards Ticmanis