Homebrewed Games - Custom Cart PCB's

[Junie]

As mentioned in a lost thread, some people are interested in creating custom/new PC board's and Cart cases.

 

I personally have looked into making a new PCB for the Homebrewed Gamers. I don't have any fancy PCB cutters or anything, but I have been exprimenting and basiclly created the Atari cart PCB with common tools I have.

 

The cheapest price I have found for the rough 2" x 2" double sided PCB would cost $0.48 and have found a way to etch the PCB for about $0.15

 

Throw in some solder (To connect the 2 sides at the points) and the material to cover the PCB and your looking around $0.85 a PCB.

 

Then add in a very small profit to cover the time involed and your around $1.00 a PCB.

 

The resulting PCB is professional grade PCB. The etched PCB is always acurate and high quality.

 

I am not sure if Randy at Hozer or any of the other Homebrewed gamers are willing to pay $1.00 for the PCB, when they can get games for $0.25 - $0.50 for both the game case and PCB.

 

I have gotten PCB software to customize the PCB so that the PCB is acutally customized for Homebrewed games. No more connecting pins together or wiring pins to other places, simply solder the Eprom in the PCB and your all ready to go.

 

If I can find a cheaper supplier of double sided copper clad PC board then perhaps the cost will be cheap enough for Homebrewed games to want the PCB's. Or perhaps they do now..

 

Of course you have to remember this is a brand new, freshly created customized, PCB-- So it will cost more.

 

If anyone knows where to buy a 2" x 2" double sided PCB for less than $0.48 please respond. The supplier I found sells the PCB in much larger boards. I simply calculated how many 2" x 2" squares would fit on the board and divied the cost of the PC board by the amount of squares.

 

Anyone have any thoughts on this or are working on creating custom/new Atari cart cases?

 

Junie

[ubersaurus]

I'm certainly interested. My friends and I are interested in programming games for the system as soon as we are finished studying up on assembly, and these would be useful to producing the games without going throught the trouble of finding games to gut, being this area tricky to find games in.

[videotwit]

Have you actually produced one yet? How much of the work is done by hand, and how much time does it take to make one from scratch on average?

 

Its an interesting proposal -- and it'd be even more interesting if you could get the cost down!

 

Any scans of the finished boards available, so we can see how they look?

 

I'm just full of questions today!

[Dutchman2000]

Any chance these could be made for the 5200?? We are looking at having PCB's made for Airworld...

[Nateo]

Actually Junie, I think anybody would be willing to pay 50 cents extra for those PCB's instead of making games like Pac-Man and Combat rare.

[Junie]

I am certainly glad to see there are people interested. If for not anything else, simply to preserve the original Atari games

 

Well I am still trying to find out exactly what changes need to be made to the original PCB's for use in Homebrewed games. If anyone knows the exact changes needed let me know and I will begin work on the new PCB layout.

 

Currently I am out of the etching chemicals and don't have the PCB layout, so here is a picture to show you one of the Atari PCB's cut to shape and put in a Atari cart.

 

I have never included pictures before so I hope this works..

 

 

Please excuse the roughness, it has been done by laying a acutal PCB on the board. Once I have the PCB layout done I can produce much better results.

 

Currently I am not sure how long it will take to create them, I would estimate it would take me about 10 minutes. Most of the time would be the etching time of the chemicals. Everything is hand done, perhaps in the future I can get actual PCB tools to shorten the time.

 

I am willing to produce the PCB's for any Atari system. I would simply need a PCB of the system to create the PCB layout, and of course I need to know what changes need to be made for the Homebrewed carts.

 

As soon as I find out what changes need to be made from the original Atari PCB's for the Homebrewed games I will start work on the layout. Once I get the layout finished hopefully I can produce some samples of the new PCB's shortly after.

 

Junie

[Chuck Gill]

I would be interested as long as it fits in a standard Atari case and was already drilled and traced to accept a 2732 and the LS7404. $1.00 does not seem unreasonable to me.

 

Randy at Hozer has custom boards made with a custom bankswitching circuit for 16k games. I believe Chris Wilkson (Hope I got his name right) makes them for him. I have been unable to find Chris on the web to see if his awesome bankswitch board is available to the general public.

 

I'm not worried about a shortage of real Atari cases. I enough of them with bad labels or that just don't work that it's not a problem. The 20 or so Pac-Invaders I made were almost all Star-Raiders carts, I seem to get lots of those with no keypad and or bad labels.

 

-Chuck

[Junie]

quote:

---

Originally posted by Chuck Gill:

I would be interested as long as it fits in a standard Atari case and was already drilled and traced to accept a 2732 and the LS7404. $1.00 does not seem unreasonable to me.

---

 

Yes the one I pictures above is in a Atari Video Pinball case (The game was dead on arrival)

 

I will create as many different PCB layouts as there are different needs. If you will tell me what changes need to be made to a original Atari PCB to work with 2732 and the LS7404, I will start work on the new PCB's.

 

Junie

[Chuck Gill]

Junie,

 

Here's a crude wiring diagram.

http://www.zutco.com/atari/Board.jpg

 

I've shown red slashes where I cut the traces and red dots where the connections are.

 

-Chuck

[mos6507]

I was wondering, how expensive is it to make a masked ROM, rather than having to burn individual EPROMs??

 

Real ROMs would be more long-lasting than EPROMs, and making them all at once would be faster than burning them to order, and you could use existing board designs without the hex inverter.

[ubersaurus]

I agree. I don't want to get any homebrews due to the eeprom dying on me after a while.

[Junie]

quote:

---

Originally posted by Chuck Gill:

Junie,

 

Here's a crude wiring diagram.

http://www.zutco.com/atari/Board.jpg

 

I've shown red slashes where I cut the traces and red dots where the connections are.

 

-Chuck

---

 

Thank you for the prompt reply. I am going to start work on it tomrrow evening once I get a tool to make acurate size measurements of the original PCB.

 

Please excuse these questions below for their "stupidity", I have never personally made a Homebrewed game. I don't have a Eprom programmer, just a PIC programmer.

 

After reading the Hozer instructions (again) and looking at your picture, only 4 of the pins appear to be used from the 14 on the chip is this correct?

 

Do you use or know what a 74ls04 hex inverter is? I assume this allows the Eprom to fit in the original ROM chip holes.

 

Also is there any differnce between the Green and Blue color lines in your picture? Perhaps one color is the front of the PCB and the other color the back?

 

Junie

[Paul Slocum]

Joe Grand, the creator of SCSIcide has custom 2k/4k PCBs. I use old Pac-Man and Defender boards which is more work but cheaper and gives me gold contacts. None of the custom boards I've seen have gold contacts, which makes me wonder if they'll eventually have to be cleaned more.

 

http://www.mindspring.com/~jgrand/atari/

 

-Paul

[Genki]

quote:

---

Originally posted by ubersaurus:

I agree. I don't want to get any homebrews due to the eeprom dying on me after a while.

---

 

erm.. I think PROM would be cheaper to use. PROM is like EPROM but it's burned only once and is nearly as durable as conventional ROM. No little window so no chance of accidental exposures.

 

I don't have any specs on PROM so I don't know if they are 100% pin compatible with EPROM.

[Arcadenut]

quote:

---

Originally posted by Junie:

I am certainly glad to see there are people interested. If for not anything else, simply to preserve the original Atari games

---

 

I'm interested. I would like to see a board that could also be used as a Mutli-Game board.

 

Here is a link to making a Multi-Cart out of an old Activision Cart:

http://members.home.com/rcolbert1/multi.htm

 

A design based off this should also allow for single game EPROM's as well. They would leave out the dipswitch and just solder one of the pins as if the dipswitch was set.

 

Hell, I'd pay $2 a cart for those :-)

 

Since I have my own EPROM burner, I would prefer EPROM over ROM.

[Junie]

quote:

---

Originally posted by Smart Patrol:

Joe Grand, the creator of SCSIcide has custom 2k/4k PCBs. I use old Pac-Man and Defender boards which is more work but cheaper and gives me gold contacts. None of the custom boards I've seen have gold contacts, which makes me wonder if they'll eventually have to be cleaned more.

---

 

Making plated gold contacts may be possiable. I have a few "cheap/easy" ideas of how to do it, I am not how sure it would turn out though.

 

Of course there has to be some actual plating way to do it. Perhaps it can be done cheaply. I'll look into this matter.

 

quote:

---

Originally posted by Arcadenut:

[QB]I'm interested. I would like to see a board that could also be used as a Mutli-Game board.

 

Here is a link to making a Multi-Cart out of an old Activision Cart:

http://members.home.com/rcolbert1/multi.htm

 

A design based off this should also allow for single game EPROM's as well. They would leave out the dipswitch and just solder one of the pins as if the dipswitch was set.

 

Hell, I'd pay $2 a cart for those :-)[QB]

---

 

This will definetly be one of my custom PCB's, a very great idea.

 

Of course instead of adding a piece of perfboard I would simply make the PCB bigger and do a redesign. A bigger PCB will undoubtly raise the cost of the PCB, so I am glad to see you're willing to pay more-- I can't produce it at the same cost.

 

At any rate as soon as I get the measuring tool tomrrow evening I can start laying out the original PCB's (I Have 3 different original versions to work with) and then start on the custom PCB's.

 

Junie

[ubersaurus]

Theoretically I would, except the smallest company I have games to is Xonox. I have coleco, mattel, atari/sears, activision, imagic, park bros. US games, and a couple others, but no ones small.

[+Andrew Davie]

I am most definitely in the market for 4K-compatible PCB layouts. I'm looking for the best price I can get on manufacture of 125 Qb cartridges. A PCB at about a buck or so would most certainly see me making an order.

[Junie]

quote:

---

Originally posted by Chuck Gill:

On the picture all connections are on the side of the board shown. (Back of board) The colors don't mean anything. The 74LS04 has 6 logic inverter gates on it, the cart only needs one of them. That's why only 4 wires are used. Atari chose to invert the chip select line on their cart design, you need to invert it through the 7404 to make it compatible with an eprom or a standard prom. If you want to see the spec sheet for a 74LS04 it's at

http://www.fairchildsemi.com/ds/DM/DM74LS04.pdf

---

 

Ok thanks for information, I knew I was wrong on my guess, very wrong. I have one last question about the 74LS04. So the 74LS04 chip is used because the Atari itself requires the chip select line to be inverted and it has nothing to do with the PCB layout itself right?

 

Now that I understand it and looking at the PCB, I can fit both chips quite easily after a new layout. Simply solder the two chips into the pins and your done

[Junie]

quote:

---

Originally posted by Chuck Gill:

On the picture all connections are on the side of the board shown. (Back of board) The colors don't mean anything. The 74LS04 has 6 logic inverter gates on it, the cart only needs one of them. That's why only 4 wires are used. Atari chose to invert the chip select line on their cart design, you need to invert it through the 7404 to make it compatible with an eprom or a standard prom. If you want to see the spec sheet for a 74LS04 it's at

http://www.fairchildsemi.com/ds/DM/DM74LS04.pdf

---

 

Ok thanks for information, I knew I was wrong on my guess, very wrong. I have one last question about the 74LS04. So the 74LS04 chip is used because the Atari itself requires the chip select line to be inverted and it has nothing to do with the PCB layout itself right?

 

Now that I understand it and looking at the PCB, I can fit both chips quite easily after a new layout. Simply solder the two chips into the pins and your done

[Junie]

quote:

---

Originally posted by Chuck Gill:

BTW Ubersaurus, I have lots of eeproms that are over 20 years old, I've never had one lose it's contents yet. Quite a few games from smaller companies came on eproms. You probably have some in your collection.

 

-Chuck

---

 

Seems everyone is talking about the Eproms going dead, glad to see that isn't the case with yours at least Chuck.

 

Has anyone actually had a Eprom go dead, or at least more often than original Atari games? All chips can go dead it seems, I have gotten 3 dead original Atari carts from a set of 20.

 

Junie

[Paul Slocum]

I've read that to erase an EPROM in the sun, you'd have to leave it out for about a year. They need a very strong UV light at a specific frequency. So light isn't a problem. But I've done a little more research and found that EPROMs do have a limited life. Manufacturers guarantee 10 years they typically last from 20 to 25 years. Not only does this mean that it would be a good idea for homebrewers to start using PROMs instead of EPROMs, but that most of the prototypes out there will eventually lose their data!! I'll look into using PROMs instead of EPROMs. I think some of the guys use some PROMs at work.

 

-Paul

[ubersaurus]

Exactly what I think. PROMs are just a better value in the long run, as this way people dont have to send their carts off to get reburned.

[ubersaurus]

Question-How expensive are PROMS? and Burners for that matter? I'm guessing those aren't cheap, or even inexpensive, so for that matter, does anyone here have one?

[cschell]

For programming the really old PROMs, one typically has to use a really old programmer. Most modern device programmers do not support the programming of the really old PROMs.

 

And actually, if you look at the datasheets, many modern PROMS are based on EPROM technology, so they're just one time programmable, windowless EPROMs. They too will eventually lose the programming charge.

 

Oh, and as long as I'm posting on this thread. If you're going to make yet another PCB for doing homebrews, please ground the unused inputs on the 7404. It's such bad practice to just leave them floating.

 

Chad