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Need help to modify a 5200 cart to play eproms.

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Hi i like to play some atari 5200 homebrew that is on 32k roms, like adventure II.

I have follow this guide here:

http://arcarc.xmission.com/Web%20Archives/Deathskull%20%28May-2006%29/games/tech/5200epromcart.html

 

Do the "universally useful way 32k"

So i hacked up a real sport baseball like the guide explain.

I used a 74S08 in place of the 7408, hooked VCC and GND of the chip it's not show on the guide but it should be necessary.

Cut track A14 track that go from /CE to the edge connector and hooked the logic gate like the diagram.

Cut the trace in the back between pin 22 and pin 20 like the guide suggest as optional to try also.

Tested using a 27c256 eprom having Adventure 2 burned to it and verify tested the rom in an emulator and work, also tested a couple of other 32k games to be safe but...

I only get a yellow screen on the Atari 5200, someone have done this kind of cart hack ?, or can help me out on what is wrong.

 

pictures of my hacked real sport baseball:

 

IMG-20190119-194302.jpg IMG-20190119-194307.jpg IMG-20190119-194319.jpg

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I finally received my 7408 last night so I was able to make mine and get it working. I went with Realsports Baseball as well, but I followed a different guide (originally posted here: http://www.azstarnet.com/~jeffryj/eprom.txt)

 

Document written by Jeffry Johnston.
With help from Eppy, kevtris and AlanD. Thanks!!

Atari 28-24 instructions
------------------------
1) Remove screw from back
2) Push in dust door with screwdriver or needlenose pliers.
3) Hold the cart, puttting one hand on each half, have a left grip on far end of cart, thumb on close, other thumb pressing the dust door. Push up with left half, squeeze down right half, push left with right thumb.
Wiggle & twist it till the first notch comes loose a bit (you'll know). Get the 2nd notch, the 3rd will come much easier & suddenly the cover will pop off.
4) Remove the RF shield, dont lose screw, spring or 2 pieces of dust door.
5) Desolder any chips from the pcb.
6) Cut the trace between Socket A, pin 28 (+5v) and Socket A, pin 27 (A14).
7) Cut the trace between Socket A, pin 22 (/OE) and Socket A, pin 20 (/CE).
8 ) Cut the trace above the hole on Connector, pin 9 (in the middle of Socket B, see above, 80/AF Enable).
9) Soldier a 28 pin Socket into Socket A.
10) Run a wire from Socket A, pin 14 (GND) to Socket A, pin 22 (/OE).
11) Run a wire from Socket B, pin 20 (40/7F Enable) to Socket A, pin 27 (A14).
12) Run a wire from Socket B, pin 20 (40/7F Enable) to 7408, pin 4 (in1?).
13) Run a wire from Connector, pin 9 (80/AF Enable) to 7408, pin 5 (in2?).
14) Run a wire from 7408, pin 6 (out) to Socket A, pin 20 (/CE).
15) Run a wire from 7408, pin 14 (+5v) to C1, wire B (+5v).
16) Run a wire from 7408, pin 7 (GND) to Outside Trace, hole (GND).
17) Insert 27256 EPROM.
18) Break off unused 7408 pins. Stick to board with 2-sided adhesive foam.
19) Reassemble with EPROM facing the cartridge label.

I will post pics later tonight, but tested with 2 different 32kb roms and both worked, at least from my initial tests (Xevious and Meebzork). I did not have any 27128 eproms available for testing so I need to order a few to try Xari Arena. Hope this helps!
Edited by brockj

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I finally received my 7408 last night so I was able to make mine and get it working. I went with Realsports Baseball as well, but I followed a different guide (originally posted here: http://www.azstarnet.com/~jeffryj/eprom.txt)

 

Document written by Jeffry Johnston.

With help from Eppy, kevtris and AlanD. Thanks!!

 

Atari 28-24 instructions

------------------------

1) Remove screw from back

2) Push in dust door with screwdriver or needlenose pliers.

3) Hold the cart, puttting one hand on each half, have a left grip on far end of cart, thumb on close, other thumb pressing the dust door. Push up with left half, squeeze down right half, push left with right thumb.

Wiggle & twist it till the first notch comes loose a bit (you'll know). Get the 2nd notch, the 3rd will come much easier & suddenly the cover will pop off.

4) Remove the RF shield, dont lose screw, spring or 2 pieces of dust door.

5) Desolder any chips from the pcb.

6) Cut the trace between Socket A, pin 28 (+5v) and Socket A, pin 27 (A14).

7) Cut the trace between Socket A, pin 22 (/OE) and Socket A, pin 20 (/CE).

8 ) Cut the trace above the hole on Connector, pin 9 (in the middle of Socket B, see above, 80/AF Enable).

9) Soldier a 28 pin Socket into Socket A.

10) Run a wire from Socket A, pin 14 (GND) to Socket A, pin 22 (/OE).

11) Run a wire from Socket B, pin 20 (40/7F Enable) to Socket A, pin 27 (A14).

12) Run a wire from Socket B, pin 20 (40/7F Enable) to 7408, pin 4 (in1?).

13) Run a wire from Connector, pin 9 (80/AF Enable) to 7408, pin 5 (in2?).

14) Run a wire from 7408, pin 6 (out) to Socket A, pin 20 (/CE).

15) Run a wire from 7408, pin 14 (+5v) to C1, wire B (+5v).

16) Run a wire from 7408, pin 7 (GND) to Outside Trace, hole (GND).

17) Insert 27256 EPROM.

18) Break off unused 7408 pins. Stick to board with 2-sided adhesive foam.

19) Reassemble with EPROM facing the cartridge label.

I will post pics later tonight, but tested with 2 different 32kb roms and both worked, at least from my initial tests (Xevious and Meebzork). I did not have any 27128 eproms available for testing so I need to order a few to try Xari Arena. Hope this helps!

 

 

Thanks for the information if you can post some pictures of your cart it could be help also :)

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Thanks for the information if you can post some pictures of your cart it could be help also :)

 

Thank you very much will try to get my mod like this :D

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Here are the pics, it keeps flipping them, sorry about that.

 

I am going to clean it and tighten it up a bit before modifying the cart.

Have redone my cart identically to yours, but have the same problem yellow screen.

May i inquire about you burn the roms using the eprom burner ?, do you used .a52 files ?, patched them ?

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Ok to be sure what was the issue i got one of this, it use a 27c512 EEPROM and every game i have burned for it shows a yellow screen.

So i have an issue on the roms i use not shure really :(

 

image.thumb.png.3cedd59efcdccbeaf4e5b0cdeae89f4c.png

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Ok in the case of the pixel past homebrew pcb to get the games working i have to concatenate the rom files to times to get a 64k one and then burn.

 

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