Apple //c Notes
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The Apple //c included many new features with its introduction. An important
one, from the SVD's point of view, is that it didn't plug directly into the
old Apple Disk II's. Note that it is
quite compatible with the old Disk II's,
it's just that the connections to the //c are different.
For more information about the old Apple disk drives, please see
Phil Beesley's site at
http://www.mandrake.demon.co.uk/Apple/drives.html.
As described above, the Apple //c didn't plug into the old Disk II's.
It used a new 19-pin (db19) connector instead.
To the left you see a picture of the back side of a 2c, click on the image for a more
detailed view.
The floppy connector is the one to the right of the RCA connector in the middle.
To connect the SVD to the Apple //c you need an adapter cable that
converts from the db19 to the old 20-pin IDC connector that the SVD uses. This cable
will have a female db19 on one end, and a female 20-pin IDC connector on the other.
You can still find people who sell this cable:
IEC (in Colorado, USA)
And it's not too terribly expensive.
I haven't contacted them, however, to determine if they actually do still carry this
cable, or if the link above is just a cob-web.
Assuming, however, that you can find a db19 connector yourself and want to build the
cable yourself, the pin-out is given below.
Note that finding a db19 connector is no small task. I did consider putting a db19
on the
Apple Dongle
but couldn't find one that was cost effective.
Note that much of this information can be found on the Internet.
I found much of it by using my voltmeter and reading schematics.
A nice treatment of the subject can be found here too:
http://apple2.org.za/gswv/USA2WUG/TIGER.LEARNING.COMPUTER/Making.Disk.II.adapter.cable.tx
NOTES:
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Another new feature introduced in the Apple //c
was a built-in floppy drive.
This drive is permanently wired as the "boot drive" or Apple people would say,
as slot #6 drive #1.
This poses a bit of a problem for booting off of the SVD...or any external drive
for that matter.
The Apple //c simply makes it difficult to boot off of an external drive.
Some of you are lucky, however, some versions of the //c had ROMs that allowed
booting from the external drive...but very few of you.
If you want to see if you can boot from the external drive, try the following:
This may or may not work for you.
For more information on the differences in the ROMS, see
http://web.pdx.edu/~heiss/technotes/aiic/tn.aiic.7.html.
Even If You Boot Externally... Even if you are able to boot externally, you may have problems.
I found it quite difficult to boot and run bootable games on the SVD connected to the external drive connector.
Half-way through the process, the game tries to get data from the //c internal drive.
Maybe someone out there can help out?
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Removing the cable is a fairly simple matter.
You simple dissassemble the case (left as an exercise for the reader).
The cable can be removed with a screw, disconnecting the grounding wire,
and VIOLA! A converter cable. HOWEVER, there is one
very important change you need to make:
2. Pull pin 17 from the idc20 connector
Click on this picture to see a close-up.
The actual pin-out for this cable is given in the table below, along with some notes
about the connections relative to the SVD.
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