How difficult would it be to produce an Atari clone?

[Mr SQL]

 

 

 

 

Maybe something is wrong with mine. It seemed to work fine and gave a nice strong and clear signal on the games that worked. I think I used an Atari made power supply on it instead of the original. Was the Gemini PSU different?

 

I don't know, if some games are working great and some aren't working at all I'd suspect the design got closer with later revisions. It would be interesting to compare the circuit boards of your Gemini's and uptoknowngood's.

[+KaeruYojimbo]

I used a Colecovision and Expansion Module 1 as my main way to play 2600 games for a while and never ran into any games it wouldn't play. In fact, I had to switch back to it when Stay Frosty 2 was released as that game doesn't play on my light sixer.

[DrSidneyZweibel]

Activision games.

 

Space Invaders works, Kaboom doesn't etc.

ca-ca. I have a Gemini and it runs all of those.

[alex_79]

Activision carts use a slightly thinner board, so they can be a bit more problematic if the cart connector (on both carts and console) is dirty, oxidized or the metal pins in the cart port just collapsed over time because of pressure and don't provide a tight connection anymore.

Edited August 13, 2017 by alex_79

[+SpiceWare]

I used a Colecovision and Expansion Module 1 as my main way to play 2600 games for a while and never ran into any games it wouldn't play. In fact, I had to switch back to it when Stay Frosty 2 was released as that game doesn't play on my light sixer.

 

I'd misplaced the ferrite beads a while back, but recently found them so this offer is still available.

[up2knowgood]

 

I don't know, if some games are working great and some aren't working at all I'd suspect the design got closer with later revisions. It would be interesting to compare the circuit boards of your Gemini's and uptoknowngood's.

 

Please, just call me up2. And I agree with Alex_79, I've had problems with Activision carts.

 

Activision carts use a slightly thinner board, so they can be a bit more problematic if the cart connector (on both carts and console) is dirty, oxidized or the metal pins in the cart port just collapsed over time because of pressure and don't provide a tight connection anymore.

 

I do find that I need to clean my Activision carts more thoroughly and quite a bit more often to keep them working compared to others. Generally worth it though, love that Pitfall II music!

[up2knowgood]

 

 

 

 

Maybe something is wrong with mine. It seemed to work fine and gave a nice strong and clear signal on the games that worked. I think I used an Atari made power supply on it instead of the original. Was the Gemini PSU different?

 

Shouldn't be, I use a new Retro 2600 power adapter with mine. Seems to work fine overall, a little touchy at times. I agree with Alex_79 that it might be the carts and not the system.

[Polybius]

They did it back in 1982, using the same off-the-shelf parts that Atari did. There's no proprietary code in the VCS as far as I know.

 

Seems to me a big sticking point would be that we can't buy the same cheap chips anymore to make a 1:1 clone or replacement.

 

The system on a chip clones like the C64dtv and Atari Flashback 2 (and only that one, not the Flashback 1, or 3 thru are the closest thing we've got outside of FPGA, and they were custom designed and not perfect.

There actually is one proprietary component to the 2600, the GTIA chip, which was the only thing Atari could bust Coleco on when they made their system, as the VTL technologies chip that powered the Expansion Module 1/Coleco Gemini was a copy of the GTIA chip.

 

They settled, and Coleco paid royalties to Atari, which worked well for both, until the '83 crash.

[PaultheRoman]

GTIA chip? Don't you mean the TIA chip? I looked into the GTIA chip, and that was something used for the Atari 8bit computers and the Atari 5200.
https://en.wikipedia.org/wiki/CTIA_and_GTIA#2600_and_TIA
https://www.ifixit.com/Teardown/Atari+2600+Teardown/3541