ralf@cad.cs.cmu.edu (Ralf Brown) (01/10/87)
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 came with the system is a TEAC 55BV, which has completely different jumpers. I asked a friend who has a PC with TEAC drives for the jumper settings, and they were the same as I had them set (DS1, HM, IU, SM, and PM all shorted). I have traced the problem to the solenoid not pulling Head 0 to the disk surface when the motor is powered up (the 55BV does not have a solenoid, just a mechanical interlock that prevents Head 0 from moving all the way toward Head 1 when there is no disk in the drive). I never noticed the lack of the characteristic click on accessing the drive, since I had become so used to it that I didn't hear it anymore, and the 55BV has no click. Now my question: Has anyone out there used a TEAC 55B drive on an AT clone? If so, please let me know the jumper settings and any other pertinent info. MUCH Thanks in advance. +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+ | ARPA: RALF@B.GP.CS.CMU.EDU "Teaching COBOL ought to be | | AT&T: (412) 268-3053 (school) regarded as a criminal act" | | Snail: Ralf Brown --- Edsger Dijkstra | | Computer Science Department | | Carnegie-Mellon University DISCLAIMER? Who ever said I claimed | | Pittsburgh, PA 15213 anything? | +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
mjg@ecsvax.UUCP (Michael Gingell) (01/12/87)
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
ralf@cad.cs.cmu.edu (Ralf Brown) (01/12/87)
In article <2543@ecsvax.UUCP> mjg@ecsvax.UUCP (Michael Gingell) writes: >In article <1037@cad.cs.cmu.edu>, I write: >> 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 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 this >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 > >Mike Gingell ....decvax!mcnc!ecsvax!mjg Thanks, Mike! Disabling pin 34 did the trick. +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+ | ARPA: RALF@B.GP.CS.CMU.EDU "Teaching COBOL ought to be | | AT&T: (412) 268-3053 (school) regarded as a criminal act" | | Snail: Ralf Brown --- Edsger Dijkstra | | Computer Science Department | | Carnegie-Mellon University DISCLAIMER? Who ever said I claimed | | Pittsburgh, PA 15213 anything? | +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+