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Path: news.uiowa.edu!uunet!comp.vuw.ac.nz!actrix.gen.nz!dempson
From: dempson@atlantis.actrix.gen.nz (David Empson)
Subject: Re: Will Apple Disk ][ work on IIGS
Message-ID: <D65o7H.Cq2@actrix.gen.nz>
Sender: news@actrix.gen.nz (News Administrator)
Organization: Actrix Information Exchange
Date: Tue, 28 Mar 1995 14:57:16 GMT
References: <mjensen2.352.0@student.uwsuper.edu> <cp62331@pro-sol.cts.com>
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In article <cp62331@pro-sol.cts.com>, Tom Kelly <tomk@pro-sol.cts.com> wrote:
>
> Actually, you CAN use a Disk II on a IIgs directly off the drive port.
> 1) You need a adapter cable to replace the existing 20 conductor cable and
> connector with one terminated in a DB-19 connector.
> 2) You can only use ONE and it must be at end of the chain.
You can use two Disk ][s if you make a double adaptor cable (one wire
needs to be moved between the first and second plugs).
Here are the details for making a single or double adaptor for
connecting a Disk ][ to a IIgs or IIc+ (or a single Disk ][ to a IIc).
The reverse (connecting a UniDisk 5.25 to a Disk ][ controller) is
also possible - reverse the sex of the connectors.
Note: make these cable at your own risk! If you get anything wrong,
you could damage your drives, disk controller and/or computer.
You require a 20-way ribbon cable, preferably no longer than 4 inches
(less length to radiate RF), a 20-way male ribbon-cable mounted plug
("insulation displacement"), and a DB-19 male plug (ribbon cable mount).
Crimp the DB-19 onto the cable (peel back the 20th wire at this end,
but do not cut it off yet).
The IDC-20 should be crimped to the other end. Pin 1 of the DB-19
should go to pin 1 of the IDC-20. (Note the difference in numbering:
the DB-19 is numbered horizontally, the IDC-20 vertically, with the
pin numbers on the IDC-20 corresponding to the wire numbers on the cable.)
A few wires need to be relocated. The best way is probably to cut the
wires a little distance from the IDC-20.
Wire 17 should be cut. Wire 19 needs to be rerouted from IDC-20 pin
19 to pin 20, so use whatever method you see fit - cut wires 19 and 20,
and then connect wire 19 from the DB-19 to wire 20 from the IDC-20.
The finished product should have connections as follows:
DB-19 IDC-20 Function
1-4 1,3,5,7 Ground
5 9 -12 volts
6 11 +5 volts
7-8 13,15 +12 volts
9 n.c. Drive 2 select
10 20 Write Protect
11-14 2,4,6,8 Stepper motor phases
15 10 Write Request
16 12 +5 volts
17 14 Drive 1 select
18 16 Read Data
19 18 Write Data
The cut pins 17 and 19 are both +12 volt inputs to the drive.
If you want to add a connector for a second drive, it has all signals
in parallel with the first connector, except that IDC-20 pin 14 should
come from DB-19 pin 9 (drive 2 select), and DB-19 pin 17 should not go
to the second connector.
I have double-checked the numbers in the table above, so if there are
any discrepancies between the table and the description, the table is
probably correct.
--
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand