atari2atari
-
Content Count
545 -
Joined
-
Last visited
-
Days Won
1
Posts posted by atari2atari
-
-
Crazy, I wasn't aware of the lack of stereo sound on the 7800. Further question, anyone got a list of which 2600 game actually use stereo sound?
Luckily, "there's a thread for that!"
http://www.atariage.com/forums/topic/113928-what-2600-games-are-in-stereo/
I don't think it's comprehensive, but it's the last time a larger discussion was had on the STEREO issue.
I just modded some 2600s with composite output and stereo sound (see link in my signature) and it's fairly straightforward on a 2600, and is interesting!
Notably, on PITFALL II the melody comes out of one speaker, while the sound effects and "beat" come out of the other. Kind of surreal! MEDIEVAL MAYHEM, a homebrew, has stereo sound for the dragon - - he (she?) has the winbeat sound go from left to right and back again as it flies across the screen. SKELETON+ also has stereo sound. Good old COMBAT, does, too, but the left/right sound of the tanks never changes what speaker it comes out of, no matter what side of the screen you are on!
-a2a
-
First of all GREAT mod. I hope to do them all to my 7800......but first is the 2600 compatible game mod is that just for the one game? or is there more that would make it worth it. Also unless he on here im wondering if little joe could pre mod my board before i order it cuz that would be helpful. I just ordered a 2600 panel jack set from him and it was delivered really fast.
lol too bad im using it for my sega mod. Its nice to get everything all in one place at a decent price.
Scott
The "2600 compatible game mod", as you call it, is a "fix" to allow a number of incompatible 2600 games in native cart form to play on the 7800.
Games such as DECATHALON, SPACE SHUTTLE, and others will glitch out or not boot without that mod in place.
With that mod in place, the only 2600 game that WON'T work, as I understand it, is DARK CHAMBERS, again in native cart format. Which, is why I installed a switch in order to "change back" to the un-modded version. A truly trivial detail to just re-allow ONE 2600 game to work on the 7800!
A HARMONY cart version of those incompatible games would be just fine, however, and you could skip the mod.
To learn more about the compatibility issues with the various models of 7800, search the forums for previous threads, there's a lot of discussion!
Here's a good "starter thread" - - http://www.atariage.com/forums/topic/74897-which-2600-games-dont-work-on-a-7800/
There's nothing that LittleJoe could pre-mod for you on his video board to help you with 2600 game compatibility - - the compatibility mod is a 7800 motherboard change!
Hope that helps!
-a2a
-
Nice write-up, thanks.
In answer to your question re: PAL carts, I have just tried a couple (I own loads more NTSC carts than PAL
)Galaga- works fine, colours correct (but I think NTSC Galaga works fine on PAL, so maybe the carts are identical, with some region checking voodoo?)
Mean 18- works OK, but colours are way way off
Food Fight-Plays, but graphics glitch, some of the play field is below the tv, colours off
Pac-Man Collection! POKEY- does not work
7800 Space Invaders-works perfectly, colours a bit off
Super Pac-Man-Perfect
Moon Cresta-Plays, but ship is below the play field
Pac-Man 720p or whatever its calle-Perfect
Meteor Shower-plays really slowly, ship is off bottom of screen
Space Duel- does not work
Interesting, thanks! Good to know what the NTSC games do on a "stock" PAL 7800!
-a2a
This little list is for PAL carts on a BIOS modded NTSC system
Ahhh! Got it, OK, great, THANKS! That's super useful!
Just to clarify and confirm yet more, do you mean a formerly PAL system that was modded to NTSC, or do you mean an NTSC machine modded to PAL with this same mod that I used? (Sorry to be so dense!)
Great write-up. I didn't know about the tia 7 disconnect thing before this. I have an original Longhorn board and have had some minor issues like what you describe. Might have to consider doing your mod there.
Out of curiosity, what it the part number of the metal plate replacement and what did it run you? My plate is in awful condition. I'd love to replace it.
Thanks!
Don't forget - - that's TIA 9, not "TIA 7", as you stated
The metal plate is - -
"Atari 7800 top case silver label CB102348 $9.95"
- - from BEST ELECTRONICS. Don't forget, Bradley has a $20 minimum order, but I'm SURE you can find something else you want, too! He's got . . . a few things.
Great post and great walkthrough, really interesting stuff. I was just looking over LittleJoe's site and am seriously considering getting a pre-assembled board for my 7800 but I noticed they only come in mono -- does the 7800 not support stereo sound?
nope
Bummer, right?
Not that we rock out the stereo on the 2600 ALL that often, but still . . . it's a nice "perk" to have! Another reason to keep that Heavy Sixer close by . . . the 7800 is certainly no replacement for a 2600, although it comes close . . . !-a2a
-
I wonder if this works with the high score cart?
It's a good question - - I don't know, sadly . . .
Probably would, however - - the Euro mod seems to have 100% compatibility for me so far! No loopholes or issues found . . .
-a2a
-
Nice write-up, thanks.
In answer to your question re: PAL carts, I have just tried a couple (I own loads more NTSC carts than PAL
)Galaga- works fine, colours correct (but I think NTSC Galaga works fine on PAL, so maybe the carts are identical, with some region checking voodoo?)
Mean 18- works OK, but colours are way way off
Food Fight-Plays, but graphics glitch, some of the play field is below the tv, colours off
Pac-Man Collection! POKEY- does not work
7800 Space Invaders-works perfectly, colours a bit off
Super Pac-Man-Perfect
Moon Cresta-Plays, but ship is below the play field
Pac-Man 720p or whatever its calle-Perfect
Meteor Shower-plays really slowly, ship is off bottom of screen
Space Duel- does not work
Interesting, thanks! Good to know what the NTSC games do on a "stock" PAL 7800!
-a2a
-
And, a return to the top, featuring some NEW composite video mod ATARI 2600 packages!
As always, thanks for looking!
-a2a
-
Greetings, Atarians!
I always enjoy a good "mod log" that shows someone's efforts in tweaking their console to be something BETTER, and so I thought I would share my 7800 project that I wrapped up a week ago.
I personally find "mod logs" to be helpful inspiration or good instructions for my own projects. Some of you may be considering the mods that I used on this project, and so you can also look at this as a "mini-review" of these mods.
I took a stock 7800 and made the following mods to it - -
- The "European OS mod" supplied by BEST ELECTRONICS
- Composite and S-Video mod board sold by our very own LittleJoe, and based on the Longhorn/batari board model
- A "disconnect" switch and case mod to clean up video interference on the video mod
- The simple compatibility mod with a switch for those 2600 carts that don't work in later revision 7800 models
- A clean, new old-stock ATARI 7800 metal case label
The Base Unit
I started with a basic 7800 that had the solder points and hole in the side of the case for the expansion port, but no expansion port . . .
The European OS mod from BEST ELECTRONICS
Best Electronics in California sells a "kit" that you can use to modify your 7800 to use the European version of the 7800's operating system
http://www.best-elec...m/7800.htm#euro
Highlights and advantages of that mod include - -
- No logo boot screen; goes right to the inserted game without delay
- Built-in ASTEROIDS game when there is no cartridge inserted
It's a relatively complex mod, requiring the removal of the current OS chip, which is soldered directly to the board, replacement with the new European OS, and then a tricky "piggyback" procedure with another integrated circuit where you basically solder a chip provided in the chip onto ANOTHER chip on the board.
If you are comfortable with soldering, it's all straightforward, just time consuming.
They even provide nice "extras" like shorter case screws to use when you re-assemble your console, which helps prevent breaking the plastic case - - some older 7800s can have brittle plastic, and if you overtighten, or sink the screw too deep, you can crack the threads or case!
Here's the instructions that came with the kit, if you want to peruse the step-by-step and see if you want to tackle it!
BEST ELECTRONICS 7800 Euro OS Mod Installation Instructions.pdf
And, here's the highlight shots of the process - -
Last glimpse of the original board before it underwent the knife
Original OS chip desoldered (note that I keep flipping the motherboard around while I work on it, and so you will see the placement of components jump left and right in the pictures!)
New IC socket in place, and new Euro OS chip inserted
The "piggyback" IC completed (first picture) and the 30-gauge Kynar wire jumper that goes THROUGH the board and runs to another chip in place (second picture). The NEW socket to the left is for the video mod, which is coming up after this section!
And those were some of the highlights minus a few other steps!
When you fire it up, ASTEROIDS for the 7800 pops up right away!
It REALLY is a straightforward mod. BEST ELECTRONICS' instructions are very detailed and thorough. Again, check out the attached PDF where you can preview the details of the work.
I really like not having to wait for the "splash screen" while games are booting, and the added plus of the built-in ASTEROIDS games is fun!
I was curious about PAL games on this unit, since now it would seemingly be "PAL-compatible" with a Euro mod, AND not have copy protection on it, which was a feature that was left out of the PAL models. PAL copies of some 7800 games are some less expensive, too!
Someone here on AtariAge had that same question, too - -
http://www.atariage....cs-euro-os-mod/
SO, I asked Bradley over at BEST ELECTRONICS to see what they knew. This is what he replied with - -
"Q. As you well know, the NTSC 7800 has a region lockout for PAL games. With the European mod in place on an NTSC unit, does that mean I can then successfully use PAL cartridges?
A. Good Atari question. Never been asked that Atari question before. I had to check our Atari 27+ Atari Super Tech to get you an answer.
He said that most Atari 7800 PAL games will run on the 7800 with the Best Composite Video mod with the Euro OS upgrade installed. But some 7800 made PAL games with Text at the bottom of the screen was hard to see (because of the 50/60 Hz screen display differences). The Atari PAL 7800 games our Atari Super tech had, Choplifter, Basketbrawl and Sentinel did have video blanking problems and were not playable. A couple more played fine but had sound problems.
All of the other Atari 7800 PAL games tested fine with full sound and normal color (normally on a NTSC console with PAL games you will get a black and white display) with no normal 50Hz (played on a NTSC 7800) video rolling screen."
Interesting!
I have not personally tried it yet, however - - I was bidding on a PAL lot last month, but the pricing got out of hand, and I backed out, and have not pursued any other PAL carts since then. I will likely get around to it here someday!
I don't know about 2600 PAL games - - I would assume they will roll, since the 2600 component of the 7800 is separate, and not PAL!
Also, I have not YET run into any compatibility issues with 7800 games on the Euro OS, but I'll update this thread if I do!
So, there you go! I give the Euro OS mod "two thumbs up" and would recommend it highly!
LittleJoe Video Mod based on Longhorn/batari Model
Now with that done, it was time to move onto the video mod.
Our very own AtariAge user "LittleJoe" is selling some excellent 7800 and 2600 video mod boards based on the classic Longhorn/batari design
His website - - http://www.electroni...entalities.com/
He's a great guy to deal with, and really goes out of his way to help you out if you need it! I had some (self-created) issues with my 7800 board initially, and he was super-friendly and fixed everything up for me!
The video mod board is really handy - - it is made to just socket right into the 7800 motherboard after you remove the IC that is there and put in a socket, which is provided in the 'kit".
Here's the NEW socket in place, ready to accept the video mod board - -
Here was my problem, though - - see that chip to the right of the socket? That's used with the European OS mod for the "piggyback stack" and once that second chip is in place . . . it's too high to socket the nice 7800 video mod board in like it should be!
My first solution was to stack a SECOND chip socket on the first one . . .
TO make a long story short, that solution and a few others I tried didn't work, and finally somewhere during my modding process, the 7800 video mod board stopped working correctly!
Basically, I lost the video output, and was only getting sound.I contacted LittleJoe, and he kindly offered to look at BOTH my board AND the video mod board. A few weeks later, he sent it all back, and had made a 7800 video mod board with LONGER pins and a secondary socket so I could socket it right into the board with no interference to the Euro OS mod!
Perfect!
Some jacks installed on the side of the 7800 case, and I was ALMOST ready to go . . .
(Note: I didn't show it here, but I always epoxy in the backs of my audio/video jacks to make them rock-solid and prevent backing out. I highly recommend it!)
I say ALMOST because there was a bit of a video issue that the perfectionist in me wanted to clean up . . . !
Add-on Disconnect Switch for TIA 9 on the 2600 Circuit of the 7800 Video Mod
Turns out the TIA 9 line causes some interference to the 7800 when it is running in 7800 mode, and the best way to deal with it right now is to just turn off/disconnect the TIA 9 line while you are running in 7800 mode (it was discussed here: http://www.atariage....s-on-video-mod/).
The video mod board actually switches "off" the TIA 9 automatically, but the automatic switch is a little "leaky" and the interference still comes through.
NOTE - - this interference is the sort of thing that only a video and audio FREAK like me is really going to notice! It's only slightly visible on pure black screens, and I feel you have to be looking for it. This "additional" mod is purely optional, but I like to do things 100%, so I went for it! I think that LittleJoe's video mod is EXCELLENT in it's current form, and this to me isn't a negative in any way! It's just the way it is out here in the wild-west of vintage gaming mods . . . !
So, the TIA 9 input is where the blue wire coming off the LOWER LEFT of the board is in this picture - -
Usually you just wire this point directly to TIA 9, but what you need to do for this mod is put a SPST (single pole, single throw) switch along that line, and flip it to "disconnect" when you are getting your 7800 mode on. Easy!
Finding the right switch, however was a bit more challenging.
I settled on a classic RADIO SHACK SPST "soft touch" in black and red, which I thought matched the classic stylings of the 7800 - -
Pop a hole in the case - -
Wire it up (I used some heat-shrink tubing to cover and clean up my spliced and soldered wires) - -
I put the switch right under the "lip" of the 7800, where it has easy access, but doesn't visually affect the look of the console at first-glance - -
Console flipped upside down to you can see how well the plastic matches - -
And, of course . . . LABELS . . . !
I guess secretly I want to be Captain Picard, as I appear to have used the word "ENGAGE" . . . a subliminal slip?
One last mod before we button up the case . . .
Compatibility Mod for Certain 2600 Games on 7800 Console
It's been covered before in detail many times here on AtariAge, but basically some 2600 games will not function on later revision 7800 units because of a motherboard change that ATARI made . . . in order to accommodate a 2600 cartridge . . . ! They were apparently trying to make the 2600 version of DARK CHAMBERS compatible with the 7800, and broke things for other games along the way.
The simple solution is to disconnect a resistor on the board, and then if you want, put a switch on it . . . so you can restore compatibility for ONE 2600 game . . .
I know, overkill, right?
Well, I wasn't using the CHANNEL SELECT switch anymore (yeah, S-Video!) and so I decided to use that as my switch.
First, disconnecting the single necessary resistor and solder a wire to it (it's the BLUE wire in this picture; the others are for the 7800 video mod and Euro OS mod) - -
Add some heat shrink tubing for cleanliness and short protection - -
The handy, already-installed switch for use - -
You need to disconnect the switch from the ground plate of the motherboard in order to use it, so cut traces on the bottom and top (bottom is only shown here) - -
Good to go!
Yes, overkill, but hey, we're shooting for 100%
Finishing Touches
So, with all that done, we can close up the case and . . . oh, wow, that metal label looks horrible and scratched!
No worries, BEST ELECTRONICS to the rescue again, with a FRESH old-stock metal label for application!
First, you of course need to tear it off, and remove the old adhesive - -
A bit laborious, but the final result looks GREAT!
I'll take that protective plastic film off the metal label someday . . . maybe . . .
WELL, that's it! I hope you have enjoyed it, or have gotten a few ideas from it.
I don't really feel this is done 100% - - I need to "fix" the cartridge slot so that there is not the issue with 2600 cartridges fitting too tightly. I was hesitant to cut up the cartridge connector at this time, though, so I will save it for another day . . . or build or obtain a "cartridge extender!"
Thanks for reading!
-atari2atari
-
3
-
-
Actually, the Combat game program does do something uncommon (in relation to more-modern games). It reconfigures data direction for one of the RIOT addresses. I can't recall if the Pac-Man game program does anything out of the ordinary, tho.
Anybody recall if some other early and common game resets DDR?
EDIT: Star Wars:Empire Strikes Back does it, too.
Interesting! Thanks, Nukey - - your posts always provide some good perspective.
As a side note, the RIOT chip tends to be the one I replace the most on 2600 consoles, followed by the TIA.
-a2a
-
Most of the time it's a blank screen and every now and then I get the bars you get if you turn on the Atari with no cart inserted.
This sort of "visual response" sounds like there is potential for one of the three critical integrated circuits - - the TIA, 6507 processor, or RIOT chip - - to have some "bit rot".
I have observed several situations where a console will work just fine for some games, but throws errors on others. The errors often manifest as "bad boots" with rolling lines, or glitches and freezing in the game.
Replacing the TIA or RIOT has resolved the problem.
I attribute it to "bit rot" - - the slow degradation of integrated circuits. Static electricity can also cause damage!
I wonder if all that cart jiggling might've broken some solder joints on the cart slot?
This also sounds reasonable to me - - different carts can use slightly different cartridge pins to access the integrated circuits of the machine, and so having some carts that work and others that don't could be caused by this, too.
Time to open her up and get to work on the motherboard!
-a2a
-
Bought a loose copy of PITFALL II for the ATARI 5200 from him.
Pleasant fellow to work with, communicated GREAT and stayed in touch throughout the process, shipped fast.
Would highly recommend doing business with him!
-a2a
-
I just got my boxed PItfall II (thanks Gary!) so I no longer need my loose one. $7 shipped. Works but needs a good cleaning.
PM sent-eth!
-a2a
-
Looks like I have lost my ability to edit the first post - - too bad!
I mean to include this "snip" of the 2600 schematics that shows the place where the ROM is also mentioned - -
Now, on to your questions . . .
...I'm just going to toss this idea in to the wind, but have tried an eprom instead? Maybe a 2516 or a 2716 eproms for 2k and 2532 or 2732 eproms? Just a thought...
Great questions on EPROMs!
From what I know so far - -
- EPROMs will theoretically work, although I have not personally tried it
- The same 2k or 4k limit applies, with no bankswitching, etc.
- EPROMs have the same pin-out as an ATARI mask ROM, with the exception of . . .
- EPROMs are "active low", which means that a low voltage current to the right pin on the IC will enable the EPROM. ATARI mask ROMs are "active high", so a high current (+5 v, I think) to activate the chip. This means that there is a high current on the motherboard headed to the chip select pin (remember, they have the same pin-out) that needs to be inverted so that the EPROM can be used.
Very interesting work so far.
As I mentioned in another thread. I would mount an inverter between 2 sockets and wire it up by bending pins so they do not pass through. Then you could use it as an adapter for EPROMS. Is there any space limitations above it?
Would you mind showing us in pictures exactly where you would wire that inverter, and specifically what part number or type of inverter you would use? "A.J. Franzman" also mentioned that you could use an inverter, but never provided details - - http://www.atariage....ost__p__2113850
I would be great if you wanted to provide some concrete details, and then I could try it out!
Here's some handy pictures for your use - -
-a2a
Pioneer, the above question is still relevant, and if you can answer it, that's great, but perhaps this would assist your illustration or wiring diagram?
-a2a
-
Looks like I have lost my ability to edit the first post - - too bad!
I mean to include this "snip" of the 2600 schematics that shows the place where the ROM is also mentioned - -
Now, on to your questions . . .
...I'm just going to toss this idea in to the wind, but have tried an eprom instead? Maybe a 2516 or a 2716 eproms for 2k and 2532 or 2732 eproms? Just a thought...
Great questions on EPROMs!
From what I know so far - -
- EPROMs will theoretically work, although I have not personally tried it
- The same 2k or 4k limit applies, with no bankswitching, etc.
- EPROMs have the same pin-out as an ATARI mask ROM, with the exception of . . .
- EPROMs are "active low", which means that a low voltage current to the right pin on the IC will enable the EPROM. ATARI mask ROMs are "active high", so a high current (+5 v, I think) to activate the chip. This means that there is a high current on the motherboard headed to the chip select pin (remember, they have the same pin-out) that needs to be inverted so that the EPROM can be used.
Very interesting work so far.
As I mentioned in another thread. I would mount an inverter between 2 sockets and wire it up by bending pins so they do not pass through. Then you could use it as an adapter for EPROMS. Is there any space limitations above it?
Would you mind showing us in pictures exactly where you would wire that inverter, and specifically what part number or type of inverter you would use? "A.J. Franzman" also mentioned that you could use an inverter, but never provided details - - http://www.atariage....ost__p__2113850
I would be great if you wanted to provide some concrete details, and then I could try it out!
Here's some handy pictures for your use - -
-a2a
-
For anyone that is interested, I have posted a VERY lengthy thread in the "Hardware" section about built-in games on heavy and light sixers - -
It is somewhat relevant to this topic, since the "unicorn" also has a spot for a built-in ROM.
I would appreciate some of your wizardly advice over there, if you are willing . . . it could be quite a cool group project!
-a2a
-
Hello!
I just posted a LONG, DETAILED thread in the hardware section about using the built-in ROM spot on heavy and light sixers - -
It's text heavy, and quite geeky, but has the potential to be very cool!
If you want to contribute, or are just curious, head on over and check it out . . .
Thanks!
-a2a
-
I would like your help to make something awesome that we all can enjoy.
Here's the PURPOSE and POINT - -
The original ATARI 2600 had a spot on the motherboard where a built-in game was SUPPOSED to be installed:
Basically, that was a spot where an integrated circuit ROM (Read Only Memory) with a game on it, just like what you find in a cartridge, could be built-in. Somewhere during production of the ATARI 2600, however, that AWESOME idea was scrapped, but the "solder pad" for the game remained behind. Then, in later revisions of the motherboard that location was removed entirely. It is only found in "Light" and "Heavy" six-switch ATARI 2600 units.
You can still install a game in that spot, though, and have it run automatically when no cartridge is loaded! There are some limits and challenges, however.
Over the years, others have documented there observations and efforts to make this work, but to date no one has written a CLEAR, SIMPLE tutorial on how it can be done so others can enjoy it. (I reference the work of others that I could find in more detail, below)
I'd like to change that, and I would propose that those who have something to CONTRIBUTE help write a definitive guide to make this work!
Here's my PROPOSAL - -
So far I've worked on this for a few weeks. I have gotten it to function - - to a point! I have major questions that are still unanswered, but I have done a lot of the first steps.
1) I would like to spell out below in tutorial format below what I have done so far.
2) And, I'd like to outline the MAJOR QUESTIONS that I think remain in order to get it to work properly
What I'd like YOU to do, if you are willing, is tackle any and all of the parts or answer questions that you feel you can CLEARLY and POSITIVELY contribute to!
What's that mean? It means that a "drive-by spray posting" of a few phrases with no illustrations or explanation, like "well, you just tie such and such to this and that, and there you go!" are not what we're looking for.
This is for "the record," so it needs to be easy to read, and people have to be able to follow the steps again.
Try reading some of these "BACKGROUND" threads below, and you will see what I mean . . .
###
BACKGROUND
There are several historic threads on the topic that provide some starting point for us.
The first is the work of AtariAge member "Longhorn Engineer" along with user "A.J. Franzman" - -
http://www.atariage....ost__p__1301781
Take a minute and scroll through it if you would like, but to summarize, there was a lot of back and forth on what was needed to be modified or added to the motherboard, some initial versions were tried with some success, and then it was abandoned. No real agreement on what you do or do not modify was reached.
Honestly, that was the best thread I have found so far after a fair bit of searching.
One other thread I found mentions the topic, along with a brief discussion of how to get larger games to work in that spot on the motherboard, but again no specifics are provided on how to DO it - -
http://www.atariage....ost__p__2113348
There is a quick mention of the "unicorn board" ATARI 2600 Jrs. in that last thread link I provided, where the "built-in" game made a brief manufacturing resurgence - -
http://www.atariage....ost__p__2113944
These are rare and not in every ATARI 2600 Jr. (don't start tearing yours apart!). Some of the "features" of this board work quite well, like accommodating larger built-in games. I have one of these boards and have gotten it to work with a built-in game (I chose PITFALL!), as I start to detail here - -
http://www.atariage....-compatibility/
And, other topics can be found about "unicorn boards" as well - -
http://www.atariage....2600jr-unicorn/
http://www.atariage....-unique-2600jr/
It's relevant because some of the "switching circuitry" that allows this to work in these late-model ATARI could be useful for this project.
[Do you have other links or references for this section? Contribute them if you do, please!]
###
QUESTIONS
Some of these questions won't make sense until you start reading the outline of the TUTORIAL below but it's good to get them out here first, I think.
There are just THREE main questions right now:
- How SPECIFICALLY (what is soldered where and why) is it possible to get games larger than 2k to work in the solder spot?
I have installed several 2k size games into the spot on a Light sixer, and had them work (COMBAT, etc.) but anything larger, like DONKEY KONG, will not work.
As mentioned above, "A.J. Franzman" alludes that it is possible (http://www.atariage....ost__p__2113348), but there are no details.
I can tell you that a 4k game DOES work in the "unicorn" - - PITFALL! is 4k, and I was able to get DONKEY KONG to work, too.
- What is the BEST way (again, with as much detail as possible with what gets modified or added and why!) to get maximum compatibility for the detecting and automatic switching of a cartridge being loaded?
I am pleased to say that by just straight installing a 2k ROM integrated circuit in the solder spot and doing NOTHING else, you actually get a LOT of compatibility. The console will automatically switch to the loaded cartridge in many situations. But not all.
I have not figured out a pattern. Here's an interesting list of games that DID boot and work with the built-in ROM in place (non-scientific, I was just grabbing carts from a box) - -
KEYSTONE KAPERS, DECATHALON, YARS' REVENGE, PRESSURE COOKER, COMBAT, FROGGER, WIZARD OF WOR
And, those that did not - -
GRAVITAR (you see the title screen, and then it rolls and glitches out), SPACE SHUTTLE, PITFALL II, and the HARMONY CARTRIDGE
The HARMONY is a known case, and is likely fixable, by the way - -
http://www.atariage....70#entry1943270
But, I have tried shorting those two pins that were mentioned, and still can't get it to work.
Once the ROM is pulled from the motherboard, ALL of the above games will work just fine, including the HARMONY, by the way.
- What is the cleanest and most direct way (once more, with DETAIL on exactly what to cut and solder!) to wire in a "kill switch" for when the above "compatibility mods" don't always work?
We need a way to absolutely and positively disable the on-board built-in ROM for times where you want to return the console to its native state.
I have looked and looked, and I just don't understand enough about disabling ATARI mask ROMs.
I think it will involve cutting some traces that go to the place where ROM is located on the motherboard, wiring some pins of the ROM to be able to be grounded (or electrified?), and putting a positive switch in there somewhere that gets flipped.
Any and all ideas on this one are welcome!
###
TUTORIAL
This will be short and sweet - - the steps thus far are simple!
Take apart your sixer and expose the motherboard.
I used this light sixer, with this serial number, and a manufacturing date of August 14, 1980 - -
Ugh, this one was kind of gross before it got cleaned, and someone had kludged in a random non-ATARI cable - -
Here is the motherboard and revision number - -
And, as shown before, the solder spot - -
I simply cleaned the solder holes with soldering braid, and then soldered in an integrated circuit socket - -
IMPORTANT - - note that the socket is BACKWARDS the way I installed it! The "key notch" that shows you which way to orient the integrated circuit when you socket it in is reversed!
I learned this because on the UNDERSIDE of the motherboard is a VERY small "1" etched into the traces that tells you where the first pin of the integrated circuit should go - -
Look in the upper left hand corner, near my "1" that is drawn in marker (IGNORE my wire coming off the pin in this picture, it's something I was doing for testing)
Now, in order to install your ROM, I recommend you actually place it in ANOTHER socket, and you will be socketing THAT socket into the one that is soldered on the board. I do this so I can have some modularity with my ROMs, and swap and try different ones.
Here's how that looks - -
I actually place a dot of solder at each of the four corners of the socketed ROM so that it doesn't come back out, too. If you are swapping these things in and out of the motherboard, it can happen, so this just secures it.
What ROM to use? Right now there is a 2k ROM size LIMIT! If we can figure it out, the maximum size is 4k. No bankswitching or fancy special chip ROMs will be possible.
EEPROMs are possible with the inclusion of an inverter [This is a section that needs to have more input on exactly WHERE and how an inverter would be placed to allow for an EEPROM]
How do you know? I used Kevin Horton's excellent list of cartridges and scanned down it for 2k ROMs - -
http://www.emulatron...tari8/sizes.txt (direct link)
Which was found here - -
http://emu-docs.org/...=All%20Consoles
NOTE: desoldering ROMs from cartridges is slow and laborious. Desolder EVERYTHING completely though, and go slow so that you don't hurt the pins on the ROM!
And, once you have your ROM and have socketed it, then you can place it on the board.
NOTE the proper direction and orientation of the "key notch" here, which is facing RIGHT! - -
DO NOT press down all the way with your socketed ROM! Just enough to make contact is for testing is perfect! If you press it in all the way, it's going to be HARD to get it back out without possibly bending pins!
Once you are certain the project is done, you can "click" it positively in, however.
And, that's it.
Really.
Turn on the console with no cartridge in it, and COMBAT or whatever will boot. Put a game in the cartridge slot and it will likely boot - - depending on the game.
Now, there was a lot of talk in that thread referenced above about cutting ground traces, adding in a zener diode, and other "pull up circuits."
I tried all that. I also tried it all WITHOUT it. So far, it works the same EITHER WAY, compatibility bugs and all.
(note my zener diode and the cut trace on the ground, just like "Longhorn Engineer" had)
Now I have repaired the cut trace, and removed the zener diode - - and I have the same exact compatibility as I did before. This is how it is operating now.
I think that the "answers" to some of the compatibility questions and the kill switch idea will require cutting traces, but for now, this "works" without it.
###
SO, that's where I am at.
Still with me?
tl;dr ? (too long; didn't read?)
I'm looking forward to any and all ideas that people have. I will happily cut and solder whatever, as long as there seems to be a decent reason behind it, so please feel free to make suggestions!
-atari2atari
-
2
-
-
I just did - - no go! KOOL AID MAN on the native cartridge does not boot! Well, it does, but it just freezes on the opening title screen.
One of the difficulty switches is used for a pause feature on Kool Aide Man. When the switch is in the pause position on startup, the game freezes on the title screen. If you flip the switch, the game should start normally.
The difference that might appear on your console is the score display. On some consoles (like Thomas Chinese Jr.) the score digits overlap. This constantly triggers the collision detection which results in Kool Aide Man constantly bouncing back and forth in the top left corner of the screen. This makes the game unplayable.
Ah-ha! I will check again to see if the difficulty switch was flipped one way or another. That must be what it was - - I always thought the "freezing" in this game was the incompatibility bug! Good to hear that it's the score display, I'll check it and let you know.
Hmm, noted! I'd be interested in knowing more about your Chinese PAL Jr.!
On all (?) 2600 Jr. consoles (NTSC and PAL) that are made in China after late 1989 the signal timing in the TIA for the shifting pulses for the movable objects seems to be a little off from older versions of the TIA. Therefore when a game starts the shifting process in such a way that some of the shifting pulses happen during the visible part of the screen, the movable objects might be positioned slightly differently. This affects all PAL 7800 consoles too, BTW.
Something similar seems to be going on in your "unicorn" console too. You can see tis in your Pitfall II video. The game doesn't do an HMOVE in every line, so not all lines start with an eight pixel blank. Pitfall II tries to hide it with displaying a black eight pixel wide copy of missile 1 in those lines where it doesn't do an HMOVE. On your 2600 these missiles are shifted one pixel to the right. If you run Pitfall II in Stella and disable missile 1 with ALT-V, you can see that there are gaps in exactly the same scanlines where the one pixel shifts are in your video.
Other games worth testing for compatibility would be the starfield effect in Cosmic Ark, the tile screen in He-Man and the cobra head in G.I.Joe / Action Force.
Thank you, sir! That is all VERY helpful and informative!
I'll try those games and report back with compatibility.
Regarding the other side conversations on STELLA compatibility and TIA revisions, it's all very interesting, too.
It is strange to me that ATARI would be so short-sighted as to make revisions to the core of the ATARI 2600 system that broke the basic programming conventions that they initially had established!
-a2a
-
Many Post Offices will not care, and you can benefit from the savings.
However, other AA members have had mail opened, either by their local Post Office, or the destination Post Office, and then the shipment denied or held.
As a result, I stopped shipping anything Media Mail to prevent possible problems!
I agree, a real bummer . . .
-a2a
-
screw parcel post, what about MEDIA MAIL. games count as media and you get a very low rate on shipping. all he has to do is leave the packages for his postman/woman to pick up, as you said it is free. it sounds to me like you let the guy bully you into a purchase. even if you are happy with the purchase the fact remains that he made you jump through hoops and you come out feeling like he did YOU a favor when YOU are the customer. sheesh, this guy has serious issues...
Just as a note, the U.S. Postal Service explicitly disallows video games to qualify for media mail - -
http://pe.usps.com/text/csr/PS-334.htm
I wish it were not so, but unfortunately it is. Maybe they will rule different in the future . .
-a2a
Edit: more detailed information is available here, too - - http://pe.usps.gov/text/dmm300/173.htm#1113500
-
1
-
-
Have you tried Kool Aid Man?
I just did - - no go! KOOL AID MAN on the native cartridge does not boot! Well, it does, but it just freezes on the opening title screen.
- As an aside, if you want to know if your ATARI 2600 Jr might be a "unicorn," pop in the HARMONY cart or a copy of PITFALL II and watch for the graphical issues as reported in this thread and the video above!
I don't think it is that simple. My own Chinese PAL Jr. behaves different on HMOVE but displays the Harmony menu nicely.
Hmm, noted! I'd be interested in knowing more about your Chinese PAL Jr.!
I would like to put Yar's Revenge in a six switch.
Is the only requirement to disable the built-in ROM grounding of cartridge pin 12?
Does something else have to be added because Yar's is a 4K ROM?
I look forward to your future projects.
No, that is not the only requirement, there is additional wiring needed to accommodate a 4k ROM in a Light or Heavy Sixer, but I am still figuring it out, so I could not tell you yet!
It's a project in process, and yes, I will be posting up my results and asking for help with installing games in the Light Sixer "as it was designed" !
I think I will get some time this weekend to share with everyone where I am at with it . . . but here's some pictures to tantalize you!
Coming along nicely! This is, of course, building on the work of others - -
http://www.atariage....ost__p__1301781
http://www.atariage....rd-differences/
However, both of those projects/discussions got VERY close or hinted at solutions . . . and then never finished and/or documented clearly what they did!
-a2a
-
1
-
-
You're welcome!
Oh, by the way, Thomas, I did try popping in a cartridge while the on-board ROM was running, and as usual I got a bus contention and scrambled screen! Nothing interesting to report there . . .
Well, I consider this thread "closed" and the question answered.
Summary - -
- The single-chip ATARI 2600 (aka ATARI 2100 "JAN") appears to (mis-)handle standard programming language for the 2600
- It is therefore incompatible with at least the HARMONY cartridge and there are some graphical glitches that have been observed with PITFALL II
- Other game incompatibilities are not known yet, but it appears that anything that depends on HMOVE in a "creative" rather than "classical" manner can cause it
- As an aside, if you want to know if your ATARI 2600 Jr might be a "unicorn," pop in the HARMONY cart or a copy of PITFALL II and watch for the graphical issues as reported in this thread and the video above!
Thanks, everyone!
-a2a
-
The music is the ‘bi bi ba tekkno remix’ of PITFALL II, from Remix.Kwed.Org, by arranger ‘chosc’ - - to find that tune, go to the Remix.Kwed.Org site, search for ‘pitfall’, and it should pop up. There is an option to download it on the right. Some of the other remixes are fun, too!
A general search on the 'toobs for 'pitfall remix' will also reveal some VERY interesting projects, I found! Be careful where you click . . .
-a2a
-
I know, I know. Just don't know how to get rid of. Thanks.
Take apart the carts, desolder and remove all the ROMs . . .
. . . and produce BANKZILLA !!!
See http://kevtris.org/2600/bankzilla.html for details . . .
I just stumbled upon this monster, and am fascinated by it . . .
-a2a
-
1
-
-
As for the "cracking" them open. In allot of cases the stems and shells are very weak. I've broken allot of Jrs opening them up.
Yup, the old plastic gets very brittle on some of them, leading to spontaneous shattering!
Luckily, the newer Jrs. seem to have better plastic? I was having issues with the "short rainbow" Jrs., but the "long rainbow" ones are mostly okay, except for the annoyance of those pesky tabs that hold the top and bottom shell together . . . hate those!
Now that we know the graphical "glitches" to watch for on certain cartridges with these single-chip units, though, with the HARMONY and PITFALL II, for example, no one needs to crack 'em open . . . unless they like to tinker, like me!
-a2a
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
What's the deal with Star Castle 2600?
in Atari 2600
Posted · Edited by atari2atari
Well-played, Mr. Williamson, well-played . . .
As is appropriate for the Internet, we require a meme for this moment . . .
I note you are approximately half-way there now on Kickstarter. This becomes more and more interesting!
Pity that Kotaku did not cover the "two sides of STAR CASTLE" but I guess that's out little family secret for now . . . !
It will be a good follow-up article at some point.
In the end, ANYthing that stimulates development on my favorite classic console and reawakens it in the minds of the public is positive in my eyes.
-a2a