Longhorn Engineer Posted May 22, 2007 Share Posted May 22, 2007 Well I was poking around my heavy sixers insides when I found a blank spot on the lower, RF shielded portion of the board. Was wondering if this has been discussed before or if anyone else has noticed this. It has 24 contacts which is the same as the rom chips in the carts I have disassembled. I haven't checked if they where connected to the cart slot yet but I wanted to see what yall thought of it. Sorry if this has been brought up before but i didn't find anything via search. Quote Link to comment Share on other sites More sharing options...
Prodos8 Posted May 23, 2007 Share Posted May 23, 2007 Well I was poking around my heavy sixers insides when I found a blank spot on the lower, RF shielded portion of the board. Was wondering if this has been discussed before or if anyone else has noticed this. It has 24 contacts which is the same as the rom chips in the carts I have disassembled. I haven't checked if they where connected to the cart slot yet but I wanted to see what yall thought of it. Sorry if this has been brought up before but i didn't find anything via search. Originally they planed to put the Combat (presumably) ROM on the board as the internal game. The idea was scrapped for some reason and the Combat cart was just included as the pack-in game. Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted May 23, 2007 Author Share Posted May 23, 2007 Thanks for answering. I wonder what would happen if you soldered a Combat ship in there and booted it up. I would assume it would play combat but would it render the cart slot unusable or would there be a kill circuit when a cart is inserted. If this wasn't my only Heavy Sixer I would probably try this out. Quote Link to comment Share on other sites More sharing options...
Starhopper Posted May 23, 2007 Share Posted May 23, 2007 Thanks for answering. I wonder what would happen if you soldered a Combat ship in there and booted it up. I would assume it would play combat but would it render the cart slot unusable or would there be a kill circuit when a cart is inserted. If this wasn't my only Heavy Sixer I would probably try this out. I have read of someone doing this before, though I can't recall where (probably in these very forums). Combat worked fine, but when a cart was inserted, they got the annoying, screaming vertical lines. Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted May 23, 2007 Author Share Posted May 23, 2007 well if i ever get hold of another heavy sixer I might have to do some experimenting. Quote Link to comment Share on other sites More sharing options...
A.J. Franzman Posted May 23, 2007 Share Posted May 23, 2007 (edited) You'll just need to switch the chip select lines between the onboard ROM and the cart port. This can be done mechanically by a switch in the port, or for most cartridges, by cutting the cart port's shield ground line, putting a pullup on it, and sensing when it goes low (most cartridges connect the shield ground and data ground lines). I do not know which method Atari had intended to use, or if there are any remnants on the board of the circuitry which would have accomplished it. BTW, this could also be done on a light sixer; the main difference between them is just the case bottom casting. Edited May 23, 2007 by A.J. Franzman Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted May 23, 2007 Author Share Posted May 23, 2007 Yah I suspected it would have to deal with the single ground line on the cart slot/rom chip. I just didn't know if disconnecting it would kill the chip to enable another rom to work without any distortion. If thats the case this shouldn't be to hard to do. I am going to take another look at my Atari board and see if I find anything that could have been used to do the switching. Thanks Quote Link to comment Share on other sites More sharing options...
A.J. Franzman Posted May 24, 2007 Share Posted May 24, 2007 First, there are two ground lines to the cartridge slot but only one to the onboard ROM. The second method of detecting a cartridge that I described, involves converting the second (shield) ground line going to the slot into a "cartridge sense" line, and using the first (data) ground line to fulfill both functions of grounding the ROM chip and the RF shield of the cartridge. I was not referring to disconnecting a ground line to disable a chip. What you do, is use the state of the new "cartridge sense" line, or the mechanical switch if using that method, to switch the "chip select" line to either the onboard ROM or the cartridge slot, and pull the other /CS line (I believe this is usually called A12 in the cart slot) high to avoid bus contention. Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted May 24, 2007 Author Share Posted May 24, 2007 (edited) Ahh when I first ran through checking the board I thought that there was only one ground. But you are right there is a ground that is connected directly to ground (shield ground) and there is one that passes through more circuitry and diodes (data ground). Well I played around a bit with my 4-switch vader. I desoldered a Cart slot from a scraped Atari board and soldered it to the back side of the Atari. If you pull the A12 pin on the cart slot up (connecting to ground) it kills the cart allowing the other cart to play. Just disconnecting it doesn't do anything. Also the Cart won't work without A12 connected to its respectful pin (obviously). I also tried the "automated" version without swapping any wires. It works but you need to add a diode to make it work correctly. There might be another way to hook it up but I found this to work. But you said that The shield ground and data ground are connected in most carts so a mechanical switch would be the 100% method. I would think that Atari was going to do the automated method as there is now reason to have two grounds (for earlier carts) for the cart slot. I am going to check my Heavy sixer and see if there is a spot for a diode but I doubt I will find anything. Thanks Franzman for helping me out. edit// addedthe schematic I used to make it work. Edited May 24, 2007 by Longhorn Engineer Quote Link to comment Share on other sites More sharing options...
NinjaWarrior Posted May 31, 2007 Share Posted May 31, 2007 Can any ROM chip go in the Heavy Sixer Quote Link to comment Share on other sites More sharing options...
A.J. Franzman Posted May 31, 2007 Share Posted May 31, 2007 Can any ROM chip go in the Heavy Sixer If you're going to just solder into the board location that's made for it (and do a switching mod so you can still use the cart port), then it would need to be a 24-pin 0.600" wide ROM from a cart board that has nothing but the ROM chip on it. For other games, such as those that have multiple chips, chip-on-board, inverter, etc., it would probably be easiest to adapt and install a second "cart port" (24-pin female edge connector) on the board, using some sort of a 90-degree standoff so you can just plug the entire board from your favorite cart into the onboard port and still have room to close the shielding. This way you could easily change the "built in" game when the mood strikes you, too. You could even make your own multi-game console that way if you have a multicart that switches games by the power switch, or a menu like the Krokodile Cart. Dipswitch-selectable multicarts would be a bit of a problem . Quote Link to comment Share on other sites More sharing options...
SINGLE TOOTH Posted June 19, 2007 Share Posted June 19, 2007 This mod would be awesome. I wanted to mod a heavy sixer for use with the synth cart. Now, I would like to use the synthcart rom and solder it on the pcb, so its always availible to the Atari, without need for a cart. Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted June 19, 2007 Author Share Posted June 19, 2007 Well I am looking in buying a light sixer to fully test this thing out. Will keep yall updated. Quote Link to comment Share on other sites More sharing options...
SINGLE TOOTH Posted June 19, 2007 Share Posted June 19, 2007 on your site you said this was only on the sears models .. Is that correct? Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted June 19, 2007 Author Share Posted June 19, 2007 I think it is in all Sixers Light/Heavy. Quote Link to comment Share on other sites More sharing options...
A.J. Franzman Posted June 19, 2007 Share Posted June 19, 2007 on your site you said this was only on the sears models .. Is that correct? I think it is in all Sixers Light/Heavy. That's right, AFAIK: all of the six-switch console motherboards have the unpopulated onboard ROM location, both Atari and Sears brands. Quote Link to comment Share on other sites More sharing options...
SINGLE TOOTH Posted June 20, 2007 Share Posted June 20, 2007 Cool, so lockhorn, you said you did get the autoswitch working??? 100%? Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted June 20, 2007 Author Share Posted June 20, 2007 (edited) I never tested that circuit for some reason. I think now is a good time to figure out if it works. edit// Yes it does work. You do have to take a Razor blade to the board to cut the ground trace where the diode is connected. Tested it in a 4 Switch by wiring a combat rom directly to the pins. Might just end up modding my Heavy Sixer so it can be the way it was meant to be Edited June 20, 2007 by Longhorn Engineer Quote Link to comment Share on other sites More sharing options...
SINGLE TOOTH Posted June 20, 2007 Share Posted June 20, 2007 Awesome. Now I wanna do it. I think I will! Im gonna post a pic, to make sure i cut the right trace. I wonder if they will sell me just the Synthcart rom? Quote Link to comment Share on other sites More sharing options...
A.J. Franzman Posted June 20, 2007 Share Posted June 20, 2007 (edited) I never tested that circuit for some reason. I think now is a good time to figure out if it works. edit// Yes it does work. You do have to take a Razor blade to the board to cut the ground trace where the diode is connected. Tested it in a 4 Switch by wiring a combat rom directly to the pins. Might just end up modding my Heavy Sixer so it can be the way it was meant to be I just saw your schematic in post #9 for the first time, and I can tell you it won't work. You need to incorporate a circuit that will route the Chip Select signal to only one or the other of the cart port, or the onboard ROM. As you drew it, it seems to me that the onboard ROM will always be active. I think part of the problem is that my post #6 was a bit of an oversimplification; the whole cutting the ground track was only for the purpose of sensing a cartridge (provides a low signal when a cartridge is present, high when not). You still need to provide other circuitry to route the Chip Select line to the appropriate location depending on the state of the new cartridge sense line. The Chip Select line itself carries digital signals which will be alternately high and low; you can not merely connect this line to ground and have a working console! Edited June 21, 2007 by A.J. Franzman Quote Link to comment Share on other sites More sharing options...
Longhorn Engineer Posted June 20, 2007 Author Share Posted June 20, 2007 (edited) I can tell you that it does indeed work. The diode has a small voltage drop across it so when you insert a Cart the onboard rom's A12 pin prefers to ground itself instead of going past the diode. Of course I only used a Combat for the onboard rom for the testing but I used several different carts for the slot. When A12 is connected to ground the console will still play the other inserted Cart. I will post some pictures of it working when I get back tonight. Edit! Ok I wired it up like in my diagram. All my carts played except Decathlon, Pitfall, and Asteroids. I know both carts work because I plugged them into my 7800 and they run. Pitfall and Asteroids had weird glitches and Decathlon refused to boot. So it is not a true 100% all compatible mod. I don't know about the safety of the mod ether as my Pac Man cart decided not to boot after I tested it in my Heavy sixer...Ms. Pac Man was fine tho... So I removed the mod because I didn't want to risk any of my other carts down the road. But other then that all the other carts played fine with no glitches or sound troubles. Attached some pictures. I wouldn't recommend anyone doing this unless you want to risk a cart. Great experiment even at the loss of a pacman cart. Edited June 21, 2007 by Longhorn Engineer Quote Link to comment Share on other sites More sharing options...
SINGLE TOOTH Posted June 21, 2007 Share Posted June 21, 2007 Cool, thanks for the work you put in, and the pics taken... Sucks its not 100% compatible and it wrecked a game. Quote Link to comment Share on other sites More sharing options...
Syntaxerror999 Posted May 21, 2012 Share Posted May 21, 2012 (edited) Deleted Edited May 21, 2012 by Syntaxerror999 Quote Link to comment Share on other sites More sharing options...
atari2atari Posted May 21, 2012 Share Posted May 21, 2012 Deleted Darn! I was hoping that you might have some insight on this tantalizing, but unfinished project of Longhorn and Benzman's! I detailed my questions on this type of project and others, here - - http://www.atariage.com/forums/topic/196567-lets-improve-on-this-lightheavy-sixer-atari-2600-wbuilt-in-gamesrom/ There are still challenges to overcome, but it could be a VERY cool accomplishment if done right . . . -a2a Quote Link to comment Share on other sites More sharing options...
flammingcowz Posted May 21, 2012 Share Posted May 21, 2012 Well I was poking around my heavy sixers insides Quote Link to comment Share on other sites More sharing options...
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