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Woww!!! Very very thanks for the Schematics!!! I really wanted it!!! The engeneer loved 8k2 resistors values!! Ahahahhahahah

How do you choose the game on this cartridge?

Today I made a discovery! I found out that of all these converted roms, centipede doesn't work on one of my consoles!! All roms converted by friend alex_79, work on 2 consoles that I have that use TIA C010444 (and also on another one that uses UM6526N) but the Centipede does not work on the console that I have that uses TIA UM6526N. All other roms work on all three consoles. That is no matter to me, I plan to change TIA UM6526 to KSC131 or C010444 but is a curious thing. I also found that the original ThunderGround (By Sega) (4K) game doesn't work on this console either. When I start, all lives die instantly one after the other and the game is over. Hundreds of other cartridges that I have work normally on this console.

I used the pcb below... The friend alex_79 member here in the forum, traced the schematics. I converted this circuit to use a 27C512 adding two more switches and now it is able to run eight 8K games. But the bankswitching is the same.. It was not changed..

I Found another one. It is a 4 in 1 The most interesting thing is that in this circuit, the switches are not SPDT devices as in the in MOST OF THEM! Here the switches are simple on/off ones.

Would be very interesting! I would like to see!

So the roms I sent you haves the same bankswitch scheme as that weird cart? Then The other ones I sent you might work too.. All of them works in the same board I tested here, so I think if one of them works all other must work too.

Please... test it and I will remove the chip from my cart to do the dump for you too.

Sent you a message.

Today, another Surprise to me!!!!! I found one more cart that DOES NOT HAVE any inverter!!!! The words on the CHIP is: AT&T ´85 QD27128A2 PGM @ 12,5V INTEL ´83 Tha games into the eprom: Frogger (no brand name) Box By ACTVISION Crackpots By PROOM FrostBite By PROOM It appears that exists a lot of 27XX that does not need any inverter to work on ATARI 2600

Woowww!! Very Cool idea!!!!

I have another 4 i 1 (4K each one game) board absolutely identical to this one but it uses a 27C128 instead 27C256 and it doesn't have the resistors.

As I told before, this is not the circuit with the floating pin. The board I test the roms haves the pins 4 and 5 connected together.

One More!!! That is a 4 in 1 (one of it 2k and 3 others 4K). It works perfect. They use a bigger 27C256 eprom than needed due to be the one they had it in the hands at those days I think. I attached here the rom dumped from it. The first eprom´s 16K is all BLANK (FF). How is it possible??? I plan to use that 27C256 in another cart and put a 27C128 here. My quest is: What is the reason to use that red pointed resistors connected from pins 6,7,8 to +B ?????????? A 27C128 will work here? 27C256_ 4in1 Bowling_Donkey Kong_Kunf Fu_Atlantis.BIN

Just to report. I don't know if this has to do with the problem but on this circuit, pins 4 and 5 of the LS00 are soldered together.

Once more Thanks friend! But tell me more please. Haves Each of the eproms exactely a half original rom codes ??? If yes, is possible to changes the roms with two 2732 ones that contains a half of Popeye (for example or any original 8K rom) code each one and it will work???

WOOOOOOOWW !!! alex_79 !!! O Tapper v3 que você me enviou hoje está funcionando MUITO BEM !!!!!!!!!!!!!!!!!!!! Sinto muito pelas fotos ruins, mas minha placa ATARI 2.6K está conectada a um dispositivo CRT !! Estou mandando as fotos !!! Muito obrigado aos amigos alex_79 e Thomas Jentzsch por me ajudarem na conversão de bankswitching para minha prancha brasileira !!! E obrigado a todos pela atenção em mim e nos meus problemas !!!!!

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.

Woooww! I will burn an Eprom just now to test it!!!! Thanks again!!!

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!

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

Here there were several like this !!

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.

I would like to ask a question about below cart. It is a 2 in 1 4K games selected by a switch. My quest is: Shouldn't there be an additional inverter circuit for this cartridge to work properly? Where is it ??