Re: Anybody aware of the description of a 19pin connector of an Apple 5.25 Disk Drive ?

[Michael J. Mahon <mjmahon@aol.com>]

Peter Dassow <z80eu@arcor.de> wrote:
> On 05.05.2013 10:39, Michael J. Mahon wrote:
> 
>>> 
>>> Ok, thx, are these signals barely just signals from a floppy drive
>>> shugart bus ? I mean can I take a non-Apple floppy disk drive like a TEAC
>>> FD55A drive, and "wire" it in an appropriate way to a 19pin connector ?
>> 
>> Not at all.
>> 
>> They are signals from an Apple Disk ][, which has a much lower-level
>> interface than the SA390/SA400 from which the Disk ][ was derived by
>> throwing out the digital control circuitry of the standard product and
>> leaving only a simplified analog board.
>> 
> 
> I was not asking for a comparison of Shugart Bus vs Apple II Disk Drive Bus.
> In 1985, I owned an "Apple II compatible", and I am 100% sure I didn't
> own any original Apple II Disk Drive.
> Instead, these Floppy Disk Drives were non Apple 3rd party ones.
> And they all had only a Shugart Bus (34pin), the flat cables were wired
> in a way it was compatible with the simple Apple Disk Controller (it was
> not an "Erphi" or another more sophisticated one).
> I have also seen already on Ebay some non-Apple Floppy Disk Drives with a
> 19pin connector (with a flat cable, which seemed to be selfmade, it was
> not a round cable with an encapsulated plug/connector).
> My main goal was to make my own cable for my LC Apple IIe Card (not
> really an Y-cable, instead just the floppy, and no, I do not need any
> "chain" for more than one drive).
> Guess I have to figure it out by myself, because nobody made this cable before :-(

I thought you were confused about the level difference between PC floppy
drives and Apple floppy drives--and you are. 

No "cable" can convert the Apple floppy interface to a standard floppy
interface. 

In 1982, I converted two standard SA400's to be Disk ][ compatible. It
involved about six pages (single-spaced) of wiring changes to the
digital/analog board in the drive. I recall spending about three hours
modifying each board--lots of wire and solder!

The net effect of the extensive modifications was to disable virtually all
of the digital controller on the board, directly exposing the head stepper
motor phases and directly connecting to the write signal and the detected
head read signal. 

Since the SA400 boards were built entirely of MSI TTL chips, all nodes of
the circuit were available for modification. Modern (!) floppy drives have
many fewer chips with higher integration levels, so it is unlikely that
such a modification would still be possible. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon