Memotech MTX series
This page was last modified 09:26, 15 September 2020 by Gdx.



Memotech MTX series are a home computers with hardware that a litte close to MSX1s. It is available in three models, the MX500, MX512 and RS128. It was released in several countries in 1983 and 1984. There is also the MX512 S2 with 256kB RAM and the Business 2. These model are very rare.

The power supply is external.

Brand Memotech
Type MTX500, MTX512 and RS128
Year 1983 (MTX), 1984 (RS128)
Region Norway
Original price At launch: £275 (MTX500), £315 (MTX512), £399 (RS128)
RAM 32kB (MTX500), 64kB (MTX512) or 128kB (RS128)
Media Memotech MTX cartridges
Video Texas Instruments TMS9929A
Audio Texas Instruments SN76489AN
Keyboard layout {{{keylayout}}}


Memotech MTX500
Memotech MTX512
Memotech RS128
Russian Memotech MTX512
Memotech MTX512 Business 2
Memotech MTX512 S2


CPU is a Zilog (Z84C0010) with 32kB/64kB of RAM (8000h-FFFFh) and a Z80 CTC (Counter/Timer circuit). CTC is a 4 channels counter/Timer. Rom size is 24kB. It contains a assembler, BASIC interpreter and its BIOS.

The Memotech MTX500 RAM is expandable to 64kB by replacing the 8 RAM by 4164s.

RAM of the Memotech MTXs (except the MTX512 S2) is expandable to 512kB with the Memotech MTX memory upgrade or MTX Memory Card.


  • RF-output
  • Analog sound and composite video output
  • Cartridge/Expansion port
  • Uncommitted parallel port
  • Centronic parallel printer port
  • Data recorder
  • 2 controller ports (DE-9)
  • Power supply input (AC 22.5 V 1A, AC 18V 0.82A, AC 9V 0.28A)

Run Memotech MTX software on MSX

Memotech MTX software can't run on MSX without changes. Some MSX software was been converted to Memotech MTX but not the reverse. No loader is available and no software was converted.

The differences between the Memotech MTX and MSXs are:

  • Memory map
  • BIOS
  • CPU frequency is a little faster
  • Z80 CTC (software are probably difficult to convert to MSX because of this CTC)
  • Used I/O ports
  • PSG is a SN76489 instead of AY-3-8910 (noise generator is on a separate voice)
  • Controllers