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pcrock

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Posts posted by pcrock

  1. Posted · Edited by pcrock

    18 hours ago, ClausB said:

    On this cart the 2600's A12 signal connects to the EPROM's /PGM input. The NM27C64Q data sheet says /PGM must be high to read data and pulsed low during programming. I think this cart takes advantage of the EPROM's side effect of disabling its output data when /PGM is low, making it effectively an active high ROM chip select, which the 2600 needs. Clever!

    Hi friend, thanks again.
    Please tell me what you think.
    As you can see in the pics I attached, this Board is locked at this time to run two 4K games but it is designed to run till four 4K games. It will works without any inverter with a 27128 ???
    The red pointed places in the pics below is the switches to select the games.
     

    WhatsApp Image 2020-09-08 at 20.20.26b.jpg

    WhatsApp Image 2020-09-08 at 20.29.12 b.jpeg

  3. Posted

    17 hours ago, ChildOfCv said:

    "Works" and "Correct" are not necessarily the same thing.  From Fairchild's TTL design notes:
     

     

    Hi friend. Once more thanks for replying. I know and I understand you are right about the TTL information you told us so I'm going to change my answer. What I meant is that this cartridge has been running Atari games for the past 37 years without ever failing. Which means that for this purpose, at least, this circuit works correctly in the way it is designed even if it is a weird thing.
    I have another older PCB whose design is also like this with these floating pins.
    But now you advised us about the question, I found a lot of other circuits here that matches exactly as you sayd! It haves the pin 4 and 5 conected together !
    Once more I hane no words to thank you all for helpping me here!

  4. Posted

    8 hours ago, ClausB said:

    It's interesting to see the economical construction and design of these Brazilian carts you've shown us in this and other threads. Most have no plated-through holes, no gold plating, no solder mask. They use minimalist circuits in strange and clever ways, often with patched game code. It brings to mind a cottage industry with limited resources but with some smart people.

    Do you (or some other friend here) understand something to tell me about the Kankaroo cart I placed at the beginning of this post????

  6. Posted

    8 hours ago, ClausB said:

    It's interesting to see the economical construction and design of these Brazilian carts you've shown us in this and other threads. Most have no plated-through holes, no gold plating, no solder mask. They use minimalist circuits in strange and clever ways, often with patched game code. It brings to mind a cottage industry with limited resources but with some smart people.

    You are absolutely correct!
    Everything you just said, accurately describes the Brazilian computer industry in the 70s and 80s! Very few resources, little money and a lot of creativity, intelligence and cleverness!

    Here we have a famous saying: "A necessidade é mãe da solução" that means something like "Needing is the mother of the solution!"!

    Nowadays we have better resources than in those days, but unfortunately it is expensive when compared to countries like USA, Canada, Japan and part of Europe.

  8. Posted

    " DIGITAL " Game Selection!!!

    Another strange to me Dynacom 2 in 1  2K games.
    That cart haves an Eprom and one more IC. Both of them were sanded and is impossible to see the chip numbers to identify it!!
    Two electrolytic capacitors 1000uF x 10v and 220uF x 10v.
    The games are Freeway and Skiing (both from Dynacom).
    The game you want to play is selected by touching the metallic contacts (red pointed in the pic I take)
    That is a Brazilian cart.

     

     

     

    WhatsApp Image 2020-09-08 at 20.29.12 (2).jpeg

    WhatsApp Image 2020-09-08 at 20.29.14 (1).jpeg

    WhatsApp Image 2020-09-08 at 20.29.14 (2).jpeg

    WhatsApp Image 2020-09-08 at 20.29.14.jpeg

    WhatsApp Image 2020-09-08 at 20.31.51 (1).jpeg

    WhatsApp Image 2020-09-08 at 20.31.51 (2).jpeg

    WhatsApp Image 2020-09-08 at 20.31.51 (3).jpeg

  9. Posted

    45 minutes ago, ChildOfCv said:

    Pin 4 of U2 needs to be connected to something.  Floating inputs are not reliable.  Should probably be connected to pin 5, or to VCC.  Makes me wonder how this board ever worked, since the connections are confirmed after removing the ICs.

    Hi friend. Thanks for replying!!!
    That circuit has been working perfect for the last 37 years exactly as described in the schematics drawn by alex_79.😄

  11. Posted · Edited by pcrock

    4 hours ago, Thomas Jentzsch said:

    The Tapper conversion runs in the coming Stella 6.3 if you manually select UA bankswitching. 

     

    The problem seems to be the "bit $c6c6" code executed in RAM. The attached ROM should fix it.

    tapper_fa0 (fixed).bin 8 kB · 3 downloads

    Hi friend. Unfortunately the rom converted still not works. But now the issue is changed if compared to alex 79 version.

    Now it remains in an Eternal looping trying to start.
    Attached video is the present issue and the picture is the alex_79 version. Both still not working yet.
    I am very thanks for trying to help me friends!

    WhatsApp Image 2020-09-07 at 18.23.45.jpeg

  14. Posted

    I own a Dynacom20200902_134443_HDR.thumb.jpg.d3068fac04e667b1f71f14790be37aa9.jpg 8k Kangaroo cart that I think is a curious thing. 

    It haves two eproms. What is the reason for that?? Why two ones? 

    All ICs numbers (even the logics) were sanded and is impossible to me to know more. 

    I have others Kangaaroo carts that uses only one eprom. 

    Would be exactlly a half of code on each of them? I yes, why?

     

    20200902_134227_HDR.jpg

    20200902_134517_HDR.jpg

    20200902_134349_HDR.jpg

    20200902_134313_HDR.jpg

    20200902_134429_HDR.jpg

    20200902_134231_HDR.jpg

    20200902_134332_HDR.jpg

  15. Posted · Edited by pcrock

    3 hours ago, alex_79 said:

    Here are some modified roms for Centipede, Tapper, Beamrider, Galaxian and Pengo:

    fa0_conversions.zip
    These should work with your board.

    alex_79 my friend!!! You are a Genious!!!!Tapper is the only one rom that does not works!!! All the others appears to works GREAT!!!!
    I converted my board to use a 27C256 and now it supports four 8K games! As you can see in the pics I sent it is working perfect thanks to you!!!
    Now I have two identical boards that fits four 8K games each.
    I think you've already helped me a lot!
    I sent you a private message to thank you once more.

     

    WhatsApp Image 2020-09-07 at 18.23.45.jpeg

    WhatsApp Image 2020-09-07 at 19.26.55.jpeg

    WhatsApp Image 2020-09-07 at 19.27.22.jpeg

    WhatsApp Image 2020-09-07 at 19.28.14.jpeg

    WhatsApp Image 2020-09-07 at 19.41.27.jpeg

    • Like 1

  16. Posted · Edited by pcrock

    12 minutes ago, Thomas Jentzsch said:

    6.3 is not released yet and it may take some time.

    Very Thanks for replying! 
    Where is the official place to download the latest versions?
    How to donate living in another country? I have interesting in donate if I can.

     

    PS. I think I found the place and the way!
    Thanks

  17. Posted

    On 9/6/2020 at 6:53 AM, Thomas Jentzsch said:

    How does one switch between the two games?

    YES! But this board can easily be converted to four games by adding one more switch. To tell you the truth I do own another identical board with one more switch that runs four 8K games

  23. Posted · Edited by pcrock

    Once more very thanks!! I want too much to get a way to make a BeanRider cart. 

    I had a cartridge like that when I was a kid. It had BeamRaider, Tapper, Galaxian and Pengo and was my favorite cart but when I was 17 years old, I gave it to a friend! He promissed to return it to me when I asked for it back.  

     I really regretted it cause he says that lost my cart and I really want to play these games again with my daughter. Here in Brazil, unfortunately any cartridge (even a pirate) that has this game (BeamRaider) is very expensive !! There are many modified BeamRaider cartridges here to sell. I saw an advertisement for one of the same brand as that was mine that is the same brand I posted here (but with four games inside. It haves two switches and I do own a cart like that here with others 8k games. The circuit is identical but with one more switch. I tested and the any rom from two carts works on any of both circuits. Does anyone here have in their collection a BeamRaider rom extracted from some cheap cartridge that works on my circuit? Or does any friend here know how to modify my circuit to work with the original rom?

    Thanks again!!!

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