How to modify a Mitsumi drive for Atari.
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Nicholas Bales
1998-01-11


This is how to connect a Mitsumi D359T6 1.44 HD floppy drive
on an Atari ST/TT or Falcon as a replacement unit.

Although, the Mitsumi drive is probably the most widespread
HD floppy drive nowadays (cheap, and included in most brandless
or homebuilt computers, it has the disadvantage of not having
any  jumpers to change the initial setting.

Therefore, you have to make a few modifications on the drive
to use it either as a replacement DD drive, or as in a HD
upgrade.

Turn the drive upside down with the drive front away from 
you and the connector towards you.

Unclip the cover with the large round hole. Underneath there
are 2 circuit boards connected with a ribbon cable.

DRIVE ID CHANGE:

On the connector board, locate a small area with 3 rows of 4
solder pads. Fire up the your soldering iron, and bridge four 
of these pads like this:

                           o o o o
                           o o=o o
                           o o o=o
                           S/T H/D
                           H/W DIS
                           H/S A/D
  
MEDIA CHANGE:

On the upper board, there are 2 switches, on for the high
density detect switch (marked HD), and the other for the
media change and write protect (marked WP and MS).

Solder a bridge between the Media Change pin and the middle 
pin like this: 
                          |     |
                          |_____|
                         W | | | M 
                         P | |=| S
                              
HD DETECT (optional):

The Mitsumi drive's HD detect pin is not connected. You 
should connect the HD switch's HD pin to pin 2 of the 
drive connector with a thin wire.

That should be it.

Please direct any comments or suggestions to
Nicholas Bales
bales@directprovider.net