You couldn't actually set the kit up as arranged in the photo, the FDX ribbon cable to the MTX was about 4" long!

A colour coordinated, 9-pin, dot matrix printer, manufactured by Panasonic based on the Panasonic KX-P1090.

Software compatible with an Epson MX80

The PSU is actually just a transformer, as printed on the case, it delivers 22.5vac with taps at 18v and 9v, smoothing. voltage regulation, etc. is done on the MTX circuit board.

The MTX manual does not include drawings for the PSU, but another user "Mark" (1024MAK) has posted this sketch of the DIN power plug pin-out at this Sinclair ZX forum thread.

I have created a separate page giving details of the PSU design & operation.

Photo courtesy of David Kimberlin-Wyer

I think this PSU was released with the MTX512 Series 2 as the logo matches the Series 2 label.

The case design and output voltages are the same as those of the original Memotech PSU - it is just the label that has had a makeover.

This photo, and the internals sketch were found on the same thread. "Mark" has also drawn a sketch for a proposed replacement PSU. The thread also lists some possible components to build the replacement PSU.

 - use this information at your own risk obviously!

An add-on that allowed a limited number of ZX Spectrum games to be played on the Memotech. You can find a couple of reviews on the Articles page.

The larger photo is from Jim Wills' website.

The Speculator PCB was profiled to fit inside a "standard" Memotech "ROMPAK" case. The photo shows a "ROMPAK" with a generic label but the finished version was identified with a "Speculator" adhesive label.

As described in the reviews on the Articles page, the Speculator is made up of two custom PALs, a 2K memory chip (Hitachi HM6116P-4 200ns SRAM) and  a couple of standard logic chips, a 74LS123 (dual monostable multivibrator) and a 74LS74 (dual flip-flop).

Technical details of the Speculator design can be found on the Speculator page.

- complete with "production" version of the Speculator case

This appears to be a Memotech branded version of the Morwood Data Recorder . This was reviewed in ZX-computing from Aug-Sep 1984. I found a copy of this article on-line at www.freetimeweb.nl

A copy of the review is available here in the Library pages

Photos courtesy of Dave Hickman

Dave's Photos  (the full size images are quite large)

MTX Computers

In reasonable condition but has a slight blemish on the keyboard label, it is fully functional, but the keyboard is fairly "sticky".

The 25-way "D" connectors on the right are for connection to the RS-232 board (not shown). The RS-232 board was an optional extra and included the interface to the FDX.

Close up of the MTX500 main circuit board, version 4000-04.

The silver box at the top is an Astec 1286 UHF modulator and the inverted circuit board below it is the video board.

This board is a "4000-04 Computer Board", fitted with 32KBytes of RAM, i.e., from an MTX500.

Now upgraded to 512K with one of Andy Key's MTX Memory Cards. Read about the trouble I had before I got to this elegant solution here.

The board actually has 64k of RAM, so is actually a MTX512 board.

You can see the 80 Column card soldered to the internal edge connector.

The black and red cable plugged into the back of the video board are for the external TV channel seletor

Video Boards

The board is plugged, component side down, into the motherboard via the two brown header plugs on the top and bottom of the board.

The BNC connector for the monitor and the phono connector for "Hi-Fi" on the rear panel are taken off this board via a plug which connects to the 4 pins on the J12 connector at the bottom left hand side of the board.

The most obvious differences are the absence of the CD4013 in the upper left corner and the replacement of the 4.434 MHz PAL crystal with a 3.579 MHz crystal for NTSC.

The two pin header is only fitted to the US version of the board and is connected to the switch on the rear panel which was fitted to US models and used to select between TV channels 3 &4

In this photo, the video board and C56 have been removed prior to the replacement of C56.

Photo courtesy of David Kimberlin-Wyer

Expansion Boards

The blue edge connector attached to the internal expansion connector on the main board. The connector pins for the 25-way "D" connector plugs is shown on the left.

The IDC connector header shown at the top is the interface to the FDX Disc System. I know of a limited number of boards that did not have the DART or other RS232 chips fitted and only supported the FDX interface. (see below)

It is not the one in the photo above, it is the board that Martin Allcorn gave me in 2014, but it is identical.

This board was available with NewWord and/or Hi-Soft Pascal ROMs installed, this is a photo of my board with Pascal fitted.

This one is fully populated, but some boards only had the 80 Column functionality and were missing the Z80 DART and support chips.

This example is soldered to the MTX internal edge connector, making its removal somewhat problematic!

This board does not have the  required ICs for the RS232 interfaces installed.

As you can see, I have replaced the two original QumeTrak 142 5.25" drives (Memotech Type 03) with two 3.5" Sony MPF920 drives (configured as Memotech Type 07).

The original Astec AC8151 PSU has also been replaced with a HEC-200SR-AT, ATX PSU.

For photos of FDX examples, see my FDX photos page

SDX Controller - Original Version

I have added a 3.5" disk drive to my controller, it takes up less space and 3.5" floppies seem to be more reliable than the 5.25" ones.

The board has the SDX CP/M ROM fitted and can therefore drive the 80 Column board in the MTX shown above resulting in a fully fledged CP/M 2.2 system with a much smaller footprint than a comparable FDX system.

This board was designed by Tony Brewer, with Tony's help, I have drawn a schematic of this board - available on the Manuals page.

Solder side of the SDX FDC05 Disk Controller

Additional photos are available on the SDX Photos page

SDX Controller - Series 2 Version

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

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

Additional photos are available on the SDX Photos page

DMX80 Printer

Paper controls on the left hand side

Control panel on the right hand side

Showing power switch and manual paper feed knob

Showing the model & serial number label, mains lead and Centronics connector.

The 8-bit switch pack at the rear of the base is used to configure the printer settings such as Print Mode (Pica or Elite) and International Character Set. The function of the individual switches is described on the Tech Tips page.

Multi-Effect Videowall Pictures - courtesy of Mike Rudkin

Most were MTX512 Series 2s, but I think some were also the RS128 model.

Each half of this controller has a Controller board and 4 or 5 Frame Memory boards, providing for 9 monitor outputs. The controller boards were multi-dropped on the ribbon cable connected to the MTX Centronics interface which is visible next to the silver UHF modulator in the photo above.

The frame buffer box looked very much like an FDX case, it was variously described as the "Black Magic box" or the (Distributed Digital Frame Store) DDFS control unit.

The lower board is the demodulator board, it accepted a composite video input and output RGBS to the Videowall controller. The large chip in the middle of the board is a ST Microelectronics PAL/NTSC One Chip Decoder, TDA3562A.

I have seen pictures of two different designs for the second control box, Peter Kretzschmar's Videowall has a simple video amplifier/splitter board installed with the demodulator board. Mike's board shown here has a much more complex second board which I assume performs the same basic function with some added complexity. Andy recalls that there was a module referred to as the "Multi Source Control Unit", this may be what is shown here.

 There are more detailed photos of Video wall systems Video wall Photos page

Miscellaneous Pictures

Later versions (Rev.05 & 06) had 3 ROMs fitted, like this MTX512.

These are 5MP photos and are over 3MB in size

(Photos courtesy of Paul Daniels)

The 4000-06 computer board is highlighted in the MTX500/512 Service Manual as a multi-layer board.

(Photos courtesy of Peter Kretzschmar)

(Photo courtesy of John Halliwell)

(Photos courtesy of Peter Kretzschmar)

On the left: 1 MB SRAM - but only 768kb usable

In the middle: RyByY -> RGB Converter

On the right: 80 Column Board

Even the 80 column board has been modified with a switch to toggle between the TMS VDP and 80 Column Board output

But if you want to see something REALLY impressive - look at this page!

This one is an imposter though, it is a standard MTX512 with one of the red keyboard covers fitted, rather than one of the demo machines built for the Russian bid.

(Photo courtesy of Jim Wills)

Probably the best photo of an RS128 on the web! (unless you know better?)

Photo courtesy of Aki Sivula

The extra length on the left hand side is the optional SDX Disc unit with in-built 3.5" floppy disk drive.

You can just see the composite video connector from the optional 80 Column Board on the right hand end plate.

(Photo courtesy of Peter Kretzschmar)

Internal view showing the combined 80 Column and RS232 board with the RGB and Composite Video monitor connections on the end plate.

This is an extended length MTX, some 3 1/2" longer than the standard MTX.

I don't think that the prototype ever made it into production.

Geoff Boyd commented "I believe this was a (very) limited run of MTX 512s with single drive Floppy disk Controller card and 80 Column card in the extended enclosure." 

Other than the standard MTX computer board, the machine shown has no additional internals fitted.

The machine has no serial number and the rear panel identification labels are missing - supporting the theory that this was a prototype model.

Information & photos from Binary Dinosaurs / Geoff Boyd.

This controller supported up to two disk drives, a 5.25" drive is shown, but it was also possible to connect 3.5" drives to the same controller.

The SDX Controller attached to the edge connector on the left hand side of the MTX computer and a ribbon cable at the rear connected to one or two floppy disk drives. The Memotech SDX "Flyer" can be seen on the Articles page.

SDX Rev 5 Floppy Controller for a maximum of 2 Drives DS DD 80 Track and 5.25" disk drive

(Photo courtesy of Peter Kretzschmar)

This also attached to the MTX edge connector and was fixed with a metal plate on the bottom of the case. I don't know if the earlier model had the bracket too.

The floppy controller could also hold 512KB of RAM which was made available as a Silicon Disk. You can also see the CP/M PROM installed on the board.

The Silicon Disk is not populated and the board looks like a very early version, you can see various wiring mods have been done the board, particularly around the 74LS244.

Photos courtesy of Peter Kretzschmar

More photos of different SDX models is on the SDX Photos page

Another sample of Peter's extensive collection

This time it is set of photos of what could be a variant of the Business/2.

Photos courtesy of Peter Kretzschmar

The floppy drives are not the standard Qume type, they look to be Epson SD-521. The motor in the SD-521 is direct drive, rather than the belt driven Qume.

This one was installed in an MTX512 sold on ebay.de in January 2013 at the same time as an FDX. It does not have a DART or supporting chips fitted, and the PAL is marked "I/F Only". 

This is not a "one-off", I know of at least one other board that has this configuration.

The same MTX512 as above was sold with no Video Display Processor or PAL/NTSC video board fitted. It would obviously have been unable to drive the normal MTX video or TV outputs.

If the machine was shipped this way, then it looks like Memotech were really cutting costs to the bone by this point.

This is a true FDX, single drive, model with an 80 Column board and supplying power to the MTX, rather than the "budget" single drive, non-CP/M version.

I would have expected the single drive to be on the left, on the twin floppy CP/M version, the drives are "B" and "C" - "A" is mapped to the boot drive.

Photo courtesy of Peter Kretzschmar

In slightly worse condition, missing the top cover, but showing the printer ribbon an carriage rails

Internationalisation

Photo courtesy of Claus Beakkel

Photo courtesy of Claus Beakkel

Photo courtesy of Claus Beakkel

The ROM part number, "N82S181N", can be clearly seen, it is an 8K-Bit TTL Bipolar PROM (1024 x 8)

Generic Photos

Downloaded from Wikimedia Commons here.

Click the text to open a medium or large size image of the keyboard.

Downloaded from Wikimedia Commons here.

A French language website dedicated to the preservation of computers and videogame machines.

(From ebay.de January 2013)

This was prior to the launch so I'm assuming that this was an early prototype. The keyboard layout is as per the production model, but the colours and Memotech logo are not and the MTX logo is missing. If you look closely, you can see what became the "BS" key is labelled in full on this keyboard, the Function Keys are numbered from "F0" to "F7" instead of "F1" to "F8"and the reset keys are identified, rather than having blank key tops as in the final version.

The Design is now the same as the original advertising brochure, the logos were changed again before the machine made it into production. (See the articles page for more.)