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The Memotech MTX Series

Memotech Photos - SDX


Original Memotech "flyer" for the SDX

My SDX Controller from

Here you will find a selection of detailed pictures of various SDX systems. The number of photos is probably a bit of overkill, but I find it interesting to see how much variation there was in the way that Memotech assembled many of their products.

If you click on the images below, the full size picture will open, be aware, many of these are quite large and may be unsuitable for display on mobile devices or with a slow internet connection, but I wanted to include as much detail as possible in the larger photos.


SDX Controller - Original Version

A selection of pictures from SDX/19985

One of the first SDX controller models, this one has the CP/M ROM fitted

Photos courtesy of Jan Seyfarth

Over head view, you can see the edge connector which is used to connect to the MTX cartridge port on the left hand side of the machine.

Rear view of the controller module, showing the floppy interface connector and a 3.5mm jack for external 5VDC input.

The Memotech floppy drives had an internal 240VAC power supply and provided a 5VDC output to power the controller module - there is not enough power available from the expansion bus connection.

View of the FDC05 disk controller board.

This board was designed by Tony Brewer, and with his help, I have drawn a schematic of the board - you can find it on this page.

The SDX was available in two version, one which provided disk functionality for MTX BASIC and one capable of running CP/M.

This controller has the CP/M ROM fitted, in order to work, the MTX needs to have 64K of RAM and an 80 Column video board fitted internally.

Solder side of the controller board

Solder side of the controller board




SDX Controller - Original Version

A selection of pictures from SDX/24985

Same model as the one above -  also capable of running CP/M

This is my own SDX controller

Slightly different aspect view of the controller

A boringly similar photo of the rear of my controller

Internal view of my controller board

Solder side of the SDX FDC-05 Disk Controller
Underside & rear view of my controller

The original version of the controller PCB : FDC-03

As described in the original Memotech product "flyer", the earliest SDXs were shipped with version 03 of the controller board - FDC-03

It appears that the ROM is a Type-2, non-CP/M, version for Australia

Photo courtesy of Chris Marsden

Solder side of the SDX FDC-03 Disk Controller

Photo courtesy of Chris Marsden


SDX Controller - Series 2 Version

A selection of pictures from SDX/32074

The SDX Controller released for the MTX512S2

This is my own SDX Series 2 controller.

The "new" style SDX controller with integral 3.5" drive. To incorporate the drive, the profile of this SDX is much "squarer" than the original SDX controller and the MTX itself.

The controller fitted to an MTX512S2 - showing the contrasting profiles of the MTX and the "new" SDX controller.

The base of the Series 2 SDX controller, there are two tapped holes adjacent to the edge connector for a metal plate used to attach the controller to the base of the MTX, intended to provide a more secure connection.
Rear view of the controller, showing the internal floppy drive cable, linking the SDX controller board to the 3.5" floppy disk drive above it. The PSU input is at the right hand side - the Series 2 controller uses the same model of PSU as the MTX itself.

Top cover removed, showing the disk drive and interface cable to the disk controller board.

The drive fitted to this SDX is a NEC FD 1036A

Internal view of the SDX with the floppy drive removed, exposing the disk controller board.

This SDX has the optional CP/M ROM as well as the optional 512k of memory installed on the disk controller. The memory on the disc controller was available for use as a RAM disk






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