Tuesday, July 4, 2023

Official and Unofficial Variants of the Atari 2600 VCS

The Atari 2600 went through many variations over its long lifespan.  Officially Atari authorized a dozen or so variations of the console, and tolerated several more when the 2600 mattered.  Most only differ cosmetically, but the sheer number of "official variants" for an early console is quite the achievement.  Today we will identify them and discuss what makes them unique. 

Standalone Consoles

1.  Atari Video Computer System/Sears Tele-Games Video Arcade (6-Switch) (1977-1980)

Both the Atari and Sears consoles have a heavy sixer and a later light sixer variants.  The "heavy sixer" has thicker, more rounded plastic on the base of the unit than the thinner and more angular plastic of the light sixer.  The photo shown above is that of a light sixer, a good comparison between the heavy and the light sixers is shown here.  The terms have nothing to do with the amount of RF shielding in the unit, the heavy and light sixers use the same metal RF shielding inside the system .  The six-switch systems come with six aluminum switches on the front of the console.  (Demo kiosks had chrome switches which do not show dirt and grime as much.)  The RF channel select switch is on the bottom of the unit and some heavy sixers do not have the switch.  The RF cable is connected inside the system but is connected via an RCA connector mounted on the PCB.  Third party consoles may solder the cable to the PCB.

The heavy sixer came with CX-10 joysticks with springs on each directional input of the joystick. The light sixer uses the standard CX-40 joystick which relies on the contact plates alone for its springiness.  The buttons always have a spring.  The heavy sixer has more recessed joystick ports than light sixers due to the thicker plastic, it may be difficult to plug later peripherals into these ports.  These systems come with two joysticks, a pair of paddles, the RF switchbox, an AC adapter and is bundled with Combat.

Sears has the word TELE-GAMES on the face of the console with a silver base around the switches, silver accents and a different and darker style of wood grain.  

The heavy sixer was sold from 1977-1978 and was usually manufactured by Atari in Sunnyvale, CA.  When the light sixer came into being most were manufactured in Taiwan.  

Inside ever 2600 prior to the last 2600jrs are three chips, the 6507 CPU, the 6532 RIOT (RAM, I/O & Timer) and the Atari CO10444 (NTSC) / CO11903 (PAL) TIA (Television Interface Adapter).  The six switch consoles also have a CD4050 hex buffer used for the luma and sync outputs from the TIA and the button inputs from the joysticks. The switches are on a different PCB from the chips and are connected by a ribbon cable.


2.  Atari Video Computer System/Sears Tele-Games Video Arcade  (4-Switch) (1981-1984)

The VCS was revised in 1981 to reduce the number of aluminum switches from six to four, with the difficulty switches being moved to the rear of the console and being plastic based.  The RF channel select switch has been moved from the bottom of the unit to the rear.  Combat is generally still the pack-in game.  Available from Atari and Sears.  

For this model, Atari moved to a single PCB design.  It eliminated the CD4050 hex buffer and significantly reduced the thickness of the RF shielding.  


3.  Atari 2600 Video Computer System (Vader) (1982-1984)

In late 1982 Atari officially renamed the system, adding the 2600 officially to the system's name for the first time. This system revised the top half of the 4-switch's enclosure to eliminate the woodgrain and the orange accents, leaving those areas black.  The joysticks also lost their orange accents.  Paddles were no longer included.  The system may come with Combat, Pac-Man or Space Invaders.  Unlike earlier systems, these systems may not have socketed 6507 CPU, TIA and 6532 RIOT chips.  There is no Sears variant of this console as Sears took a different path:

4.  Atari 2800/Sears Tele-Games Video Arcade II (1982-84)

The Atari 2800 was released only in Japan, but Sears brought this redesign back to the States in the form of the Video Arcade II.  The console has separate expert and novice difficulty switches for each player and joystick and paddle selection buttons which light up when active.  The Select and Reset switches also reside on the top of the unit for eight distinct buttons.  There are four joystick ports and the power switch is next to those ports.  Uniquely they are on the front of the console instead of the rear as with the standard six-switch, four-switch and Jr consoles.  The B&W/Color and RF channel select switches are on the bottom of the console.  The system came with Space Invaders.

The controllers which came with this system are quite different than the standard Atari consoles.  These systems came with a pair of combined joystick and paddle controllers, with the joystick being able to be pushed as well as twisted.  The controllers come with a pair of buttons, but both buttons correspond to a single input.  The third and fourth ports are only for the paddle portion of these controllers.  The joystick and paddle buttons are just directing the fire buttons on these controllers to either the TIA (joystick fire) or the RIOT (paddle fire).  Curiously these consoles use a barrel-jack power supply instead of the Atari-standard mini-jack connector.


5.  Atari 2600jr. (1986-1990)

After Warner Communications sold the assets of Atari Inc.'s Home Video Game and Computer divisions to Jack Trammiel in 1984, Trammiel's Atari Corp. re-released the Atari 2600 as the Atari 2600jr. in 1986 as a budget console when the NES became popular.  The enclosure was redesigned to be smaller, lighter and sleeker, replacing all aluminum switches with simple plastic slider switches and a membrane strip for the momentary contact Game Reset and Game Select switches.  A power LED was added and the RF cable was detachable without opening the system..  The system came with only a single joystick and no pack-in game but at $50 it was now a budget console.

The 2600jr. comes in three variants, the earliest version of the system uses a aluminum "short rainbow", then came the aluminum "long rainbow" and finally a black plastic rainbow.  It is uncertain if the short rainbow was released in PAL countries or the black rainbow was released in NTSC countries.  The black rainbow consoles were usually manufactured in Ireland.  

Some late 2600jrs will come with a single chip which consolidates the previously separate CPU, RIOT and TIA chips onto a single die.  A few compatibility issues may result but these consoles are rare.  The CD4050 returned for video buffering duties for luma and sync.  The joystick buttons are not buffered by the chip but one of the six buffers is used for the reset circuit.


6.  Coleco Gemini Video game System/Columbia House Home Arcade (1983-84)

Coleco was able to clone the Atari 2600 because the 2600 used off the shelf CPU and RIOT chips and its TIA had been cloned by VLSI Technology.  This system has the power, B&W/Color, Game Select and Game Reset switches on the top of the console, two controller ports and difficulty select switches on the front of the console and a detachable RF connector and the RF channel select switch on the back.  The power supply uses the mini-jack connector, so Atari 2600 power supplies work with this console.  The console was typically bundled with Donkey Kong, Mouse Trap or Front Line.  Columbia House rebranded this console as the "Columbia House Home Arcade" and sold it via its mail order business but not many were made.

The controllers which game with these systems have both a joystick and a paddle dial and a fire button.  Coleco released a splitter cable to allow you to use 3 & 4 player paddle games.  In order to use the paddle fire button, you must push the right directional on the joystick portion of the controller for players 1 & 3 or the left directional for players 2 & 4. That is how paddle fire buttons are wired on the 2600.

Consoles with Backwards Compatibility

7.  Atari 7800 (1984, 1986-1991)

The Atari 7800 contains a 6502 CPU, a 6532 RIOT and a TIA for almost 100% 2600 game compatibility.  The 7800 also has 4K of RAM and a 4K BIOS (16K for PAL) and the advanced MARIA video chip which are activated only when 7800 games are inserted into the console.  The cartridge slot has extra connectors on each side for 7800 games, but the interior pins will take 2600 cartridges.

On the 7800, the controller ports are on the front as are the difficulty selection switches.  The RF channel select switch and the detachable RF modulator RCA connector is on the rear of the system.  The top of the console has switches for power, "pause", game select and game reset.  The pause button is the equivalent to the B&W/Color switch, but unlike the switches on the 2600s, the pause button is a momentary switch.  The power connector is non-standard.  

The 7800 joysticks have two independent fire buttons but are backwards compatible with 2600 controller ports.  Later releases of the 7800 (and 2600jr) in Europe came with an NES-style D-Pad with two fire buttons.  2600 games released prior to the console's discontinuance will not support a second fire button in the way Atari implemented it in the 7800. Both buttons function the same with 2600 games.  There are three revisions of the 7800 console, one with the expansion port, one without the port but holes for its installation and a third with little evidence of the expansion port.  

While the 7800 has some compatibility issues with certain 2600 games, the existence or lack thereof of an expansion port is not a reliable indicator of which consoles have issues and which do not.  Atari added a timing circuit to fix the 2600 version of Dark Chambers when run in the 7800.  It also fixes the 2600 version of Kung Fu Master.  Either due to the timing circuit or the design of the cartridge slot, Activision cartridges and the Starpath Supercharger may have difficulty working reliably in the 7800.  

Console Add-on Modules

8.  Coleco ColecoVision Expansion Module #1

The Gemini was not Coleco's first attempt at getting Atari 2600 games to run on its own hardware using the VLSI clone of the TIA.  The Expansion Module #1 plugged into the Expansion Port of the ColecoVision. The device has five switches on the front, all except Power.  The ColecoVision main unit supplies power to the Expansion Module and its Power switch activates the Expansion Module.  The Expansion Module transmits video and audio through the expansion port to the RF module on the ColecoVision.  

There are two controller ports on the front of Expansion Module.  ColecoVision's standard controllers are compatible with Atari 2600 hardware, but only their joystick and fire buttons are compatible with 2600 games.  The number pad portion of the controllers are not 2600 compatible.  Some third party cartridges, such as those from Tigervision, did not fit in the slot for the Expansion Module #1 and Coleco gave away extenders which could accommodate these cartridges.

The 2600 was built on the 6507, 6532 and TIA chips.  The first two chips were free to purchase but the TIA chip was a proprietary chip that Atari designed in-house and did not sell outside the 2600.  VLSI cloned the chip die of the TIA and rearranged the die so it did not look exactly like Atari's die under the microscope.  The legality of the Coleco device was the subject of a lawsuit by Atari, but both parties settled and as part of the settlement Coleco agreed to license the patented technology in the TIA from Atari so they could continue to make the Expansion Module and Gemini consoles legally.  Coleco's own ColecoVision was built entirely from off-the-shelf components, only its BIOS and the console video game crash kept the cloners at bay until Coleco was no longer relevant.

9.  Atari 5200 VCS Cartridge Adapter

Not to be outdone by Coleco, Atari released its own 2600 add-on for the Atari 5200.  This device plugs into the 5200's cartridge slot.  Inside the adapter are the three chips which make up the 2600, the 6502 CPU, 6532 RIOT and TIA.  The Adapter has two chrome switched on its front for Game Select and Game Reset.  One controller port and one difficulty selection switch is located on each side of the adapter.  Cartridges are inserted on the top of the adapter.  Power and RF modulation are supplied by the 5200.  The adapter does not have a B&W/Color switch but the device could be modded to add one.

Without modification, this Adapter only works with 2-port 5200s.  Atari Service Centers could perform the modification for the 4-port 5200s.

10.  Mattel Electronics Intellivision System Changer

Following Coleco's lead, Mattel released its own 2600-compatible add-on for its console, the Intellivision.  This device is inserted into the cartridge slot of the Intellivision.  The top of the unit has the five standard buttons and the two controller ports are on the front of the unit.  Power and RF modulation are supplied by the Intellivision.  

The System Changer is out of the box only compatible with the Intellivision II and its enclosure was designed to match the styling of the Intellivision II.  Mattel Service Centers could modify the earlier Intellivision and its clones and successor (Sears Super Video Arcade, Tandyvision One, Sylvania Intellivision, INTV System III) to work with the System Changer.  The chips inside the System Changer are not in standard plastic packages but bonded directly to the PCB and covered with epoxy.  

If you are a glutton for punishment, you can use the deatchable disc controllers of the Intellivision II for 2600 joystick controllers.  It is not known whether Mattel licensed the patents in the TIA from Atari but Atari never tried to take the System Changer off the market, unlike the Coleco add-on.

Plug-in Plays

11.  Atari Flashback 2 & Atari Flashback 2+

A plug-in-play does not have a cartridge slot.  The only official & legal plug-in-plays which do not use software emulation are the Atari Flashback 2 & 2+ consoles.  They are the only consoles with composite video and audio output using a hardwired mono AV cable.  They have all six buttons of the original consoles but the B&W switch is on the back.  The two controller ports support original Atari joysticks, paddles and other controllers.  Two joysticks were included.  A menu screen allows you to select from the 40 built-in games (+ 2 or 3 hidden games).

The Flashback 2 and 2+ had points placed on the board which can be used to solder a cartridge slot.  While this will not be 100% compatible with Atari 2600 cartridge, it will work with most games.  There were three or four official board revisions of the console, each fixing bugs and game issues.  The third revision was present in both the 2 and the 2+.  There are no PAL versions of the Flashbacks.  The 2+ is distinguished by its dropping of titles from Activisions, some improvements to the homebrew games and the addition of sports-focused titles.  

The original Flashback used a NES-on-a-Chip and games were completely reprogrammed to function with the very different hardware of the NES.  The Flashback 3 and later consoles use ARM-based software emulation.  

So how many US variants?

Six-switch has four variants: Atari Heavy, Sears Heavy, Atari Light, Sears Light

Four-switch has three variants: Atari, Sears, Vader

Jr. has two US variants: Long & Short Rainbow

Video Arcade II counts as a variant

The answer is 10 official variants, or 13 if you count the official 5200 VCS Adapter and Flashback 2 and 2+.  If you add the Mattel and Coleco clones, you get 15.  The 7800 gives you 3 more.

Foreign Systems

There were PAL versions of most of these consoles.  These use a TIA that displays PAL color video signals and have a separate oscillator to produce a PAL color video carrier and games for PAL 2600s  which output at 50Hz.  Atari released a heavy sixer, a light sixer, a four switch, the Vader, the long rainbow and the black Jr. in PAL countries. It also released a PAL 7800 but did not release the 5200 as a PAL console.  The Intellivision II was not released as a PAL console so the add-on would not have been made available but Coleco did release a PAL Expansion Module #1.

French SECAM units were only released as four switchers and Vaders.  The SECAM consoles use a PAL TIA but do not use its color output.  Instead it uses the three luma outputs from the TIA to generate 8 colors.  There was a 2600jr. released for France, it used the short rainbow shell and had a SCART plug wired directly to the mainboard.  The console output PAL video, not SECAM, so you could see almost all the colors (104) a TIA could produce (128 for NTSC TIAs).

Japan received a version of the 2600 before the 2800.  It was imported by Epoch in its heavy sixer form but was unsuccessful.  Atari handled the 2800 itself but against local competition from Sega, Nintendo and Epoch, it failed miserably.  Japan uses NTSC, so the only difference between a Japanese 2600 and a US 2600 would be the frequencies supported in the RF modulator.  These systems would come with 100 VAC power supplies.

Brazil uses PAL-M, which combines an NTSC line count and refresh rate with a PAL color carrier.  Gradiente, under its Polyvox label, released a licensed Vader.  It had to compete against many unauthorized clones (CCE, Dactar, Milmar, Dismac, Robby) consoles which beat it to market and thus was not a huge seller.  Some Polyvox systems have the power adapter's internals mounted inside the 2600 and run a wire out of the back.  The Polyvox uses an NTSC TIA with converter circuitry added to produce a PAL color signal.

There was an official Vader-style release of the Atari 2600 in Turkey by ME-TA A.S. Unlike all the other consoles where cartridges were interchangeable or theoretically so, the Turkish 2600 swapped a pair of address lines (A6 & A7) from the connector, thus making cartridges from other regions incompatible with the Turkish console.  Similarly Turkish 2600 cartridges will not work without a converter in another type of console.  Turkey is a PAL country and the local distributor apparently wished to discourage importing cartridges from mainland Europe.

1 comment:

  1. My first Atari 2600 was the Coleco Gemini. My system came with both Donkey Kong and Mouse Trap as pack-ins. I still have both cartridges.

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