markb@tplrd.tpl.oz.au (Mark Bower) (05/07/91)
Using a 3.5" 1.44MB floppy drive in an A2000
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I recently posted a net-request for info pertaining to adding a non-amiga
floppy drive to the A2000. Thanks to all those who responded. Since then
I have made a small modification to the 1.44 MB drive which allows it to
be used wth most amiga software. In fact, it works with anything that uses
the trackdisk.device I/O handler, but some games (mainly copy protected ones)
don't seem to like it (they don' crash, they just don't recognise the disk in
the drive). Anyway, enough of this rambling, heres the modification:
Introduction:
~~~~~~~~~~~~~
This modification allows one to use an IBM type 3.5" 1.44 MB floppy disk drive
to be used in an amiga which will allow it to read standard AmigaDOS disks.
At this stage, this does not allow the amiga to have a High Density floppy
drive.
Procedure:
~~~~~~~~~
The drive used was a Chinon FZ357 (Revision A) 1.44 MB 3.5" High Density
floppy. However, the procedure given below is fairly generic and could be
applied to other drive types.
Disclaimer : I take no responsibility for anyone causing damage or injury to
either equipment or biological life while performing this procedure or while
reading this document(!).
o 1. Place the drive upsidedown on a flat surface.
o 2. Remove the (almost) rectangular protective shielding that covers
the circuit board that has the floppy drive connector, power supply
etc. This should be held on by a single screw at the side of the
drive.
There is no need to remove any other shielding or covers from the
drive.
o 3. This part of the procedure requires a small amount of soldering:
On the FZ357 Drive, locate Jumper J5. It is located at the
rear of the drive next to about 6 jumper pads thus:
----------------- Power Connector
|Floppy Conector| C J ||||
|is here | 3 6 Rear of drive. ||||
----------------- |*|*|*|*|
J5--| | | | |
|*|*|*|*| (may be more jumpers/capacitors)
|| to front of drive.
\/
NOTE: The silk screen on my drive didn't have J5 marked
very close to the actual jumper (it was about 8 mm away)
but there are no other jumpers close to it so there
shouldn'y be too much confusion.
At the moment, J5 should be OPEN (i.e. the two pads not connected
together). using a soldering iron and a small piece of tinned copper
wire (or as you see fit) connect the pads of jumper J5.
On (almost) any other drive :
Locate the jumper which connects to pin 2 (the CHNG line on the floppy
connector) of the floppy data cable connector. If you can find this
jumper (not all drives may have this), trace the other side of it
and see if it connects to the RDY line of the floppy connector (pin
34 of the floppy data cable connector). This jumper should be
bridged by wire and solder as for the FZ357 drive. (I recommend
using a digital multimeter/signal tracer to trace the signals
from the connector to the pins to ensure that you are connecting
the right signals together. (Maybe even a switch soldered across
the jumper so that you can test the drive while it is operating.)
o 4. Next, set the drive select jumper for the drive numbe you wish
to use this drive as. This can be selected via a set of jumpers
(usually) located at the rear or side of the drive. If you
have a floppy connector cable with a twisted section in it, then
you can select the drive to be 0 (the lowest drive number
is 1 in some drives).
o 5. Finally, on the A2000, connect a jumper socket over conector
C301 on the motherboard (located near where the floppy connector
cable connects to the motherboard. This allows the A2000 OS
to automatically mount the drive at boot time.
o NOTE : The power supply connector on some drives is reversed -
On the Chinon FZ357 it was not (I could connect it directly)
but on other drives please check this.
The drive should now read and write your amiga floppies like (almost) the
standard amiga drive.
Unresolved Issues:
~~~~~~~~~~~~~~~~~~
* Compatibility with some games. Anyone out there solved this
problem ith similar drives ?
* Has anyone had any success in using the High Density capability
of these type of drives ? I'll try to write a driver when I
get time but i'd rather not re-invent the wheel if someone
else has done it.
Cheers to all,
Mark.
| /\
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Mark F. Bower. (markb@tplrd.tpl.oz.au) | \/
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