---
title: Microdigital TK-85
categories:
- Computers
types:
- Home Computer
origins:
- Brazil
years:
- '1983'
cpus:
- Zilog Z80 A
params:
  name: TK-85
  company: /companies/microdigital
  company_name: Microdigital
  specs:
  - label: NAME
    value: TK-85
  - label: MANUFACTURER
    value: Microdigital
  - label: TYPE
    value: Home Computer
  - label: ORIGIN
    value: Brazil
  - label: YEAR
    value: '1983'
  - label: END OF PRODUCTION
    value: Unknown
  - label: BUILT IN LANGUAGE
    value: Improved version of the ZX81 Basic
  - label: KEYBOARD
    value: 40-key QWERTY rubber keyboard with up to 5 function per key
  - label: CPU
    value: Zilog Z80 A
  - label: SPEED
    value: 3.25 MHz
  - label: RAM
    value: 16 KB up to 48 KB
  - label: ROM
    value: 10 KB
  - label: TEXT MODES
    value: 32 columns x 24 lines
  - label: GRAPHIC MODES
    value: 64 x 44 dots
  - label: COLORS
    value: Monochrome
  - label: SIZE / WEIGHT
    value: 23 (W) x 14 (D) x 3 (H) cm / 500g
  - label: I/O PORTS
    value: Expansion port, Tape-recorder, RF video out, Joystick
  - label: BUILT IN MEDIA
    value: None
  - label: PERIPHERALS
    value: Microdigital printer, all ZX81 peripherals
  - label: PRICE
    value: Unknown
  tabs:
  - photos
  - adverts
  - hardware
  - docs
  photos:
  - title: LARGE VIEW
    subtitle: ''
    text: ''
    image: null
  - title: SIDE VIEW
    subtitle: ''
    text: ''
    image: null
  - title: TOP VIEW
    subtitle: ''
    text: The case and keyboard design are very similar to the Sinclair Spectrum's.
    image: null
  - title: KEYBOARD CLOSE-UP
    subtitle: ''
    text: ''
    image: null
  - title: REAR SIDE
    subtitle: ''
    text: ''
    image: null
  - title: POWER SUPPLY UNIT
    subtitle: ''
    text: ''
    image: null
  adverts:
  - title: 'ADVERT #1'
    subtitle: ''
    text: |-
      From the magazine 'Micro Sistemas' of March 1983

      Thanks to **www.mci.org.br**
    image: null
  hardware:
  - title: MICRODIGITAL JOYSTICKS
    subtitle: ''
    text: ''
    image: null
  docs:
  - title: MICRODIGITAL TK-85 BASIC MANUAL (PORTUGUESE)
    url: http://www.datacassete.com.br/uploads/manuais/zx81/tk85.pdf
    cover: null
    text: |-
      [**MICRODIGITAL TK-85 BASIC MANUAL (PORTUGUESE)**](http://www.datacassete.com.br/uploads/manuais/zx81/tk85.pdf)written by Microdigital

       compiled/archived by www.datacassete.com.br\
       type of document : PDF\
       size : 19.6 MB\
       source : [www.datacassete.com.br](http://www.datacassete.com.br)

      **... READ THE ONLINE VERSION BY CLICKING BELOW :**
  comments:
  - author: Carlos Deabreu (usa)
    date: Thursday 4th June 2015
    text: I Still have one with a thermal printer old K7 player and small black $ white tv.
  - author: YERZMYEY/HOOY-PROGRAM (PL)
    date: Sunday 2nd September 2012
    text: |-
      It''s a really beautiful desing.\
      A cool clone of ZX81.
  - author: Rey D (USA)
    date: Friday 3rd September 2010
    text: This was my first computer!!!! My dad bought it for me when I turned 16 (I was living in Argentina at the time). I learned how to program in Basic on this little computer. Great memories! :)
  - author: Cleidson A. Peixoto (Brazil)
    date: Wednesday 28th April 2010
    text: |-
      Mr. Carlos,

      Yes, it is right - the TK 85 haven''t a PSG. But it came prepared to allocate one - There is a space for the same PSG from the MSX (The AY), and there is a memory adress that is never used - This adress can be used to control the PSG.
  - author: Carlos Cristo (Campinas - Brazil)
    date: Wednesday 31st March 2010
    text: |-
      Good to see it again..!!\
      The information is correct, but this part\
      "and the built-in three-voice sound generator. " is not.\
      It never had three-voice sound generator... even Tk-90x (the zx-spectrum clone) had... only MSX series had this.. : )
  - author: Jerónimo Milea (Argentina)
    date: Friday 14th March 2008
    text: It was my first computer too ^\_^ it brings me very nice memories :)
  - author: Xavier Garreau (La Rochelle, FRANCE)
    date: Thursday 10th November 2005
    text: I wrote my first programs on this computer. Nice to see it again :)
  - author: Rodrigo Quinteiro (Sao Paulo - Brazil)
    date: Saturday 8th January 2005
    text: The TK85 was my 1st computer. All that I learnt in BASIC I need to thanks to this small computer. I still having the TK85 at home, but the keyboard is not working anymore.
  oc_id: 976
  source:
    url: https://web.archive.org/web/20230608085718/http://www.old-computers.com/museum/computer.asp?c=976
    date: '2023-06-08'
---

After the **TK80**, [TK82](/museum/microdigital-tk-82/) and **TK83** the TK85 was the last [ZX-81](/museum/sinclair-zx-81/) compatible machine Microdigital produced.

However it wasn't only a simple copy of the ZX-81 but featured several useful enhancements. Its rubber keyboard and case were similar to the Spectrum's and were much more pactical for intensive use. The 10 KB ROM held an improved version of the Sinclair's Basic with strings management and editing facility, as well as some primitive graphic commands.

Several additional routines allowed to record tape programs up to 4200 bits per second, manage a joystick interface and the built-in three-voice sound generator.

Thanks to the TK85, Microdigital started to lead the Brazilian home computer market, front of Sinclair and its US branch, Timex.

Thanks to **Joao Roberto** for most of the pictures and information.