Newsgroups: comp.sys.apple2 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: Sender: news@actrix.gen.nz (News Administrator) Organization: Actrix Information Exchange Date: Tue, 28 Mar 1995 14:57:16 GMT References: X-Nntp-Posting-Host: atlantis.actrix.gen.nz Lines: 71 In article , Tom Kelly 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