Mindless Mayhem releases it's eigth file:
EL CHEEPO 5.25" DRIVE FOR PS/2'S
brought to you by The Beastmaster


DISCLAIMER: YOU MAY ATTEMPT THIS MODIFICATION AT YOUR OWN RISK. THE
            AUTHOR IS IN NO WAY RESPONSIBLE FOR ANY DAMAGE INCURRED
            AS A RESULT OF ANY SUCH MODIFICATION.


Interface specifications: IBM PS/2 to external 5.25" drive

The following is a description of how to hook up an external
5.25" diskette drive to an IBM Personal System/2 with a minimum
of cost and components.

The diskette interface in a PS/2 is essentially the same as in
the older PC.  The 34 pin signal and 4 pin power connectors have
been replaced by a single 40 pin connector.  In addition, output
signals from the drive have been changed from open collector to
tri-state.  To perform the interface, connect pins 1 through 34
from the PS/2 straight through to pins 1 through 34 of the
external drive.  Pins 8, 26, 28, and 30 also need a 10K ohm
pullup resistor to +5 volts.  Connect the power supply pins as
follows:

IBM PS/2                           5.25" external diskette drive
40 pin diskette drive connector    4 pin power connector
       
37 ------------------------------- 2  (ground) 
38 ------------------------------- 4  (+5 volts) 
39 ------------------------------- 3  (ground) 
40 ------------------------------- 1  (+12 volts)
  
A 40 pin card edge is needed to mate with the 40 pin connector
at the B: drive slot.  An IBM (old bus) prototype card or other
suitable card with 0.1" edge contact spacing can be used if cut
to size.  Mount the pullup resistors on this board, then run the
data and power cables from the board to your external drive.
Try to keep cable lengths as short as possible.  Don't forget to
boot your Reference Diskette and configure drive B: as 5.25"
external.  If you're having problems configuring it as 5.25" disk,
set it up as 1.44mb drive and see if that works. If all else fails,
keep reading and see end of file. Also, be sure to remove the
termination resistor(s) from your external drive if it is so
equipped.  Maybe I'll write an .ADF file. Maybe not. We'll see.
For most of the wiring, i would stronly suggest you use ribbon
cable; just buy a floppy drive wire cable with connectors, and cut
off one of the two connectors, and affix it appropiatly to the card
or whatever you use.

The optimal interface would include additional buffering and
shielded cable, but if you are that serious I suggest you buy
a real computer that can handle an internal 5.25" drive.
Note:  The interface described herein has been neither approved
nor disapproved by IBM.  


   -The Beastmaster


note: If you have any serious problems, go after this guy who
originally came up with the idea.

David Jaque-ass Brunell CIS ID: 74630,64
Brunell, Webber, Smif, Jackson, Jabarr, and Associates
P.O. Box 2751
Palm Beach, FL 33480


LALALALA. Hope you enjoyed another Mindless Mayhem release. Be on
the lookout for more and be sure to call Destiny Knights, home
board for all Mindless Mayhem releases, at 708-307-3768 NUP: Fourth
Dimension. NO STILLWATERS WELCOME If you haven't read any
of our other releases, you're missing out. Lates.


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