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Stay Frosty 2 doesn't work on six switchers?


thecrypticodor
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The stand alone cartridge doesn't work on my sixer either. During development I did periodically test SF2 by loading it onto the Harmony*, which should have been the same as loading it onto the Melody board. It worked fine that way, so there's an unforeseen difference between the Harmony and Melody.

 

Last night batari was able to get another Atari set up that replicates the problem, which puts us that much closer to finding a solution.

 

* via USB, not the SD card

Edited by SpiceWare
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My new Stay Frosty 2 cartridge works great on my A/V modded 4-switch woody, but if you need any extra help in the debug effort, I have both a heavy sixer and a light sixer I can pull out of storage.

 

It seems to be pretty much just Heavy and Light Sixers. I thoroughly tested 11 different systems yesterday, including two Light Sixers, five Four Switchers and four 7800s. Worked fine on everything but the sixers. I did have issues with one of the four-switch systems, but I think that system may not be entirely right in the head, so I'm not sure that one is a good data point.

 

..Al

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I think someone also mentioned that their Byte Before Christmas didn't work on a sixer also .

Waggie reported Byte Before Christmas not working.

I reported Byte Before Christmas working after twice failing.

 

The issue has been figured out.

The solution is under development.

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Alright, we have discovered why our current version of the Melody board is having issues with Light and Heavy Sixers. While Fred Quimby was researching this issue, he looked at the Heavy Sixer schematics and found a circuit that does not exist on any later Atari systems (four-switcher, Jr., 7800), and doesn't really seem to serve a useful purpose in the Sixers. This circuit also seems to cause problems with other games as well--for instance, River Raid II.

 

While we continue to work on a solution that fixes this issue from the cartridge side of things, there is a very easy mod you can do to your Light or Heavy Sixer that will fix these compatibility issues. After doing this mod to two different Light Sixers, every game I threw at the system ran fine, including River Raid II. iesposta modified his Heavy Sixer with the same results.

 

Here's the back of the circuit board:

 

sixer_compatibility_mod.jpg

 

Simply bridge the two circled solder joints with a wire and you'll bypass this circuit. Very easy to do mod if you have any soldering experience.

 


Here's an image after the mod has been performed:


sixer_compatibility_mod_finished.jpg


Example of River Raid II before and after:


river_raid_2_fail.jpg


river_raid_2_good.jpg


And Stay Frosty 2:


light_sixer_frosty.jpg


If anyone performs this mod, would love to hear your results.

 

..Al

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I'm guessing this was already tested, but does the same thing happen to the Stay Frosty 2 demo if it's directly dumped to the Harmony Cart instead of loading it from the menu? My mains are a Sears light sixer and a 7800 from China that is somehow able to play both Robot Tank and Dark Chambers 2600. I also have a 7800 that hates Robot Tank (don't remember if it plays Dark Chambers or not), another 7800 that likes Robot Tank (not sure about Dark Chambers), an Atari light sixer, and the Colecovision Expansion Module for 2600 games.

 

Edit: Nice! I'm glad you figured out the problem and that's an easy fix on the hardware side of things. I'm getting the Harmony menu does something different that lets the games work? I remember River Raid II working from the harmony, but I'll check to be sure.

 

Edit 2: River Raid 2 works from the Harmony menu on my Sears light sixer.

Edited by BrianC
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What component(s) or circuits does this mod short out?

They are series inductors that are tied to the 5V and GND lines for the cartridge. Fred believes this circuit may be the cause of numerous problems with carts running on Heavy and Light Sixers, including bankswitch homebrew games. The fact that River Raid II works after performing this mod is telling.

 

..Al

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Could have something to do with how quickly (at power on) and how cleanly +5v is applied to the cartridge. I'd have to look over the schematics. Hopefully it doesn't stress any other components or shorten their life. Perhaps the reverse is true and it can lengthen the life.

 

The engineer put the inductor there for a reason. Issues could manifest much later. Just say'n to be certain and careful with modding. Or maybe this mod fixes a latent problem seeing as how the part was removed in later iterations?

Edited by Keatah
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Could have something to do with how quickly (at power on) and how cleanly +5v is applied to the cartridge. I'd have to look over the schematics. Hopefully it doesn't stress any other components or shorten their life. Perhaps the reverse is true and it can lengthen the life.

 

The engineer put the inductor there for a reason. Issues could manifest much later. Just say'n to be certain and careful with modding. Or maybe this mod fixes a latent problem seeing as how the part was removed in later iterations.

Here are the schematics:

 

https://atariage.com/2600/archives/schematics/index.html

 

Sixer Schematic:

 

Schematic_Atari2600_1000.png

 

Four-switch Schematic:

 

Schematic_Atari2600A_1000.png

 

You can see the inductors tied to the cartridge on the Sixer and not the Four-Switch.

 

..Al

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The inductors are not on any other console but sixers. It was also an engineer who decided that the inductors were not actually necessary. Inductors wired like that can cause overvoltage and brownout conditions, the latter of which I think might be the problem.

 

I don't know why the engineer put it there, my guess was something to do with FCC requirements. It also could be that the first 2600 was designed to hot-swap carts while the onboard ROM was running. Of course the onboard ROM was never used, and maybe the circuit simply wasn't questioned until the 4-switch was designed.

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I'll agree that it's for FCC requirements and noise suppression - and suppression of noise in the cart getting back into the console. All at the cost of a slower rise time in initial power-up. And I bet this slower rise time is affecting Melody.

 

No doubt Melody has stricter timing and power requirements than the masked roms of the day. A good question to ask is why Harmony is different than Melody? And is it worth modding Melody to work with the inductors? There *are* going to be people that won't want to disassemble their consoles no matter how straightforward this mod is.

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There *are* going to be people that won't want to disassemble their consoles no matter how straightforward this mod is.

Certainly I am not expecting people to modify their console in order for homebrew games to work on them. However, there are many hardware hackers here, so I'm sure some people will do the mod (especially as it's easy to do/undo). Not sure what the ultimate solution is going to be just yet.

 

..Al

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What I said before, and I'll be more clear: The issues have been figured out.

When Al says he is not sure what the ultimate solution is going to be, it definitely will not be modifying your hardware.

This 2600 hardware discovery is just one part that has been figured out, and answers a long-standing question as to why River Raid II, California Games, and on rare occasion homebrews fail on the 6-switchers. And I, for one, am glad Al shared this information!

Best case will be a software fix that delays code until the voltage stabilises.

Worse case is a Melody revision (that has already been figured out and tested) but that will take time and money I'm sure AtariAge does not want to lose for these holiday games.

It's only been a day or so, and mere hours since carts in issues have been figured out.

Maybe it will be something between best and worst case?

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Yes, the hardware mod is not our "answer" but merely suggested for those who have a SF2 cart and a sixer, and want to play the game before, or on Christmas. I think it's worth doing the mod for its own merits, though, as it may increase the compatibility of the console.

 

As for why Harmony and Melody are different, well, Harmony has a pair of decoupling diodes that separate USB power from console power, but Melody doesn't have these diodes. Well, an unintended consequence of the diode, I believe, served to decouple a brownout condition from the inductor. Fortunately I think it's possible to do a software workaround.

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