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A > ATARI  > 400


This mini forum is intended to provide a simple means of discussion about the Atari  400 pong. If you want to share your own experience or memories, or add relevant information about this system: post a message!

  Click Here to add a message in the forum


Tuesday 1st September 2020
RonF (Illinois, USA)

I have a 400. I made a keyboard for it as per the article in December 1982 Creative Computing ( I bought a kit from some company I cannot remember that upgraded it to 64K (cutting traces and soldering some wires was involved) and installed it. I also bought the Assembler cartridge for it and took a course in how to program it. I had a lot of fun with that machine. It''s in a box in the garage, I should get it out and see if it still works.

Friday 5th October 2018
David Mc (UK)

I had an Atari 400 when I was about 13. Me and my older brother used to love writing games for it and using it to switch on light bulbs etc. via relays. The joystick ports were ideal for this!

When we started working for an electronics firm, we actually used a 400 to control and test digital PABX telephone exchanges and later design 6502-based, fully automated test rigs for the firm.

Recently, my mother was clearing out her attic and asked me if ''this'' was any use? It was my old Atari 400! I thought it was long-gone!

This year I opened it up, repaired it and finally upgraded it to 48K!

Tuesday 20th June 2017

Atari 400 is the best home computer for videogame until Commodore 64.
I love its vintage look membrane keyboard!

Sunday 10th April 2016

I grew up in middle class family 80’s America. As far as I’m concerned the Atari 400 was THE COMPUTER OF ITS DAY (before the C64 anyway) nothing else came close with graphics and sound. We all wanted the 800 (or an Apple) but all my family could only afford was the 400. We weren’t alone, the 400 outsold the 800, big time. One would troll the back pages of computer magazines (no internet then!) where 48K DIY upgrade kits were available. My uncle, infuriated that we had to buy a “special tape recorder” as a peripheral, wrote a letter to Atari asking for the specifications of the I/O interface so he could build our own cable for use with any generic tape recorder$ Atari complied. Talk about customer service, try that with Apple or MS. The membrane keyboard was perfect for teenaged users like me$ it was impervious to soda and fast food fingers, as was the steel reinforced unit itself. It survived a spinning $ down a flight of stairs unscathed! Like all good things, it was too good to last. Our house was broken into and amongst the few items stolen was my beloved 400. Heaven has a special place for emulator developers, they’ve retrieved my 400 for me and countless others!

Saturday 22nd June 2013
Eduardo (NY)

Does anyone know if there is a demand for the Atari 400, never opened and the recorder (never opened also) would go for ?
Is there anywhere I can sell this?

Thursday 3rd January 2013
Ryan Madison

You guys are fags!!!!!

Monday 3rd October 2011
Patricia Hobbs (Australia)

I have an atari 400 which I would be happy to donate to a museum

Monday 3rd October 2011
Patricia Hobbs (Australia)

I have an atari 400 which I would be happy to donate to a museum

Tuesday 20th January 2009
Kostas Poularakis

My first computer was an Atari 400 in 1983. I loved that computer. I eventually got an Atari 800 XL with a printer and disk drive. Later on I got a modem too. That was so much fun.

Sunday 4th January 2009
Jose Luis Llamas (Mexico)

My first computer was a ATARI 400, one day a disassembly to drive a toy crane, it works!! I made a lot of experiments... those wonderful days...

Friday 21st March 2008
Peter Hurst (UK)

I loved my 400 - first machine I tried hardware hacking. As stated elsewhere the Joystick ports were capapble of being used as inputs - I remember toying with test circuit and relays to try and do useful stuff. I have a recollection of a joystick port interface to something but I can't remember what. It was a really good hybrid - the 8K roms with Atari games went under the flap and loaded almost immediately, hours of Defender!

I later bought the 1050 floppy disk for the Xl range and used it to back up roms with a little machine code bootloader for running the copies and an Atari Basic program to generate the copies.

The machine had a hardware and software interlock on the cartridges, the flap had to be shut to power up and the rom checked a memory location for a cartridge and jumped straight to it if it found one. Turned out a simple switch on the address lines was enough to defeat the check and allowed the machine to boot normally with a cartridge in place.

I loved the keyboard at first, but don't forget I came from a ZX-81 and the raised edges on the 400's keys made all the difference, it also lasted many years without failing. I was so sad to see the 400 go when I got an ST

Saturday 21st April 2007
Dave MacLachlan (USA)

This was the first computer I ever owned. I couldn't afford the tape cassette recorder for storing programs, so I became very adept at memorizing whatever I was working on, and retyping it to work on it some more. Fun stuff!

Thursday 28th December 2006
Roy Lowenstein (USA)

I had one of these way back when. I bought it from an employee of Atari that stuffed it with 48k. I had the printer, interface, disk drive, tape drive and modem (can't remember the brand on it) that could go up to 450 baud. The interesting thing about Atari is they had their own version of ASCII called ATASCI and could transmit graphics to other Atari machines when the rest of the world was still looking at rudimentary drawings using letters and numbers. I had a pimative bulletin board writen in assembly language that was a lot of fun. I hated that damn keyboard!

Friday 13rd October 2006
J Martin (Connecticut)

The Atari came with 8k upgradable to 16k. In fact the chips that came on the 8k systems were the same as the 16k model, except the upper half of the addresses was disabled (there were two 8K chips if I remember correctly). Supposedly these 8K chips were factory defects where there was a bad bit in the upper half. There was a simple mod (something like jumpering or replacing a diode) that would re-enable that memory, which I did. Sure enough I discovered that there was exactly one stuck bit in a byte in the upper half of RAM that would always stay 'on', which would corrupt BASIC tokens or machine code, causing the computer to freeze when it was executed. I eventually learned to work around in BASIC programs by carefully placing REM statements in BASIC code and JMPs in assembler so that the bad byte wouldn't accidentally fall in real executable code or corrupt program data. Pain in the neck, but worth it for double the memory. Eventually my dad found a replacement RAM chip for it and everything was good.

Saturday 9th April 2005
David (Oklahoma)

After playing on the 2600(and being hooked on Activision's Stampede and others LOL) the Atari 400 was a giant leap it seemed. I remember aquiring the tape drive and playing a game called Zaxon or Zaxxon that came on a cassette tape that had to be loaded into the 400 b4 playing...i think i actually spent more time loading or trying to get it to load than actually playing the game, but when it DID work it was an awsome 3-D flight simulator kinda thing that had amazing(for the time,of course) graphics!

Monday 17th January 2005
adamofevil (usa)
Atari MULE Online

I am sure that a lot of you Atari users once had an Atari 8-Bit computer back in the day. Maybe you still do. You might remember a classic game called M.U.L.E. A game that you wish would have been ported over to the PC but never was.

If you are a M.U.L.E. fan like I am, you probably used to have hordes of your friends over your house to play the best 4-man multi-player game ever written! After playing this game for hours upon hours, days upon days, years upon years, finally everyone grew up or grew apart and stopped getting together to play.

If you are a M.U.L.E. fan like I am, you probably have done a bit of M.U.L.E. re-searching on the internet, in hopes for one day someone to create an internet capable version of this great classic.

Well, I have some very good news for you. If you run Windows (98/XP) operating system, THE WAIT IS OVER!!!

Thanks to the authors of the Atari800WinPlus ( and Kaillera (, you can now play the greatest multiplayer game ever made with 4 players OVER THE INTERNET! This is not a clone, it is the ORIGINAL M.U.L.E. un-modified! Same graphics, same sound, same game! The only difference is that it looks a lot better on your computer than it did on your TV back in the day!

If this interests you, please hop on over to where M.U.L.E. fans from around the world have been gathering and playing online!

Some of our members include the authors of the most popular M.U.L.E. web sites such as World of Mule ( and Extreme MULEing ( and M.U.L.E. Fans ( Even the creator of the recent M.U.L.E. clone game Space HoRSE ( has joined up with us!

Ahh, the feeling of playing with 4 human players again is quite exhilirating! SO, what are you waiting for? Join us now!!

See you there!


Monday 28th June 2004
John Risby (Earth)

As Tristan Smith says (on the main page), the Joystick ports were I/O ports and could be used for many things. The 400 was my first home computer (I was 9 or 10). I wired up one of the ports to my bedroom door to create a computer controlled burglar alarm!

Tuesday 11th May 2004
Nicole Harrington (Ca, MD at the time)

I used to work for a company that was warranty service for Atari. We started with the games then added the computers. I beleive it was 1983 that we started working on POS (point of sale) displays as they called them for atari that were the coolest thing I had ever seen. It was an Atari 400 computer on a display with a big TV. Below was a special interface board and a Pioneer laser disk player. You could walk up to the atari (which would cycle through its default come take a look message) and it would then play the appropriote response back that had been recorded on the video disk. It was quite fast. The "horrible" keyboard made it durable against spillage and such.
The funniest thing was there was a problem that no one could solve becouse the person who designed the 400 to video disk player interface was angry and refused to tell them how it worked. It turned out that a peice of foam was needed to stop the VD player top from opening if it thought it was at the end of the disk.
As far as I know this was quite ahead of its time!

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