Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!mcnc!ecsvax!mjg From: mjg@ecsvax.UUCP (Michael Gingell) Newsgroups: comp.sys.ibm.pc Subject: Re: Adding 360K drive to AT clone: Help needed Message-ID: <2543@ecsvax.UUCP> Date: Mon, 12-Jan-87 08:51:54 EST Article-I.D.: ecsvax.2543 Posted: Mon Jan 12 08:51:54 1987 Date-Received: Mon, 12-Jan-87 21:49:58 EST References: <1037@cad.cs.cmu.edu> Distribution: na Organization: UNC Educational Computing Service Lines: 20 Summary: Cut the trace to pin 34 In article <1037@cad.cs.cmu.edu>, ralf@cad.cs.cmu.edu (Ralf Brown) writes: > I have recently purchased an AT clone (see my previous post for a > rave review) and am trying to add a second disk drive. I have > two TEAC 55B drives from my previous computer, but neither of them > will work in the AT, either as drive A or drive B. The drive which The AT uses 2 additional lines to the floppy drives to support the special HD 1.2 Meg drives, Pin 6 (I think) is used as the reduced write current control to tell the HD drives when to write to regular 360 K floppies. Pin 34 is an output from each drive which tells the AT when a disk has been changed. Pin 34 is the culprit. Most pre-AT 360K floppy drives have thisis connected as an alternate drive 3 select. If you plug such an unmodified drive into an AT it will hang. You must either cut the wire to pin 34 in the ribbon cable, or do what I did, that is cut the trace to pin 34 on the drive. All it takes is a sharp knife. Jumper the drive as number 1 (counting from 0), and away you go .... Mike Gingell ....decvax!mcnc!ecsvax!mjg