Atari 2600 home made cartridge: dont works

[7800fan]

You say you have 0 ohm on every address. Did you check if there's accidental short between address lines? Say for example, A8 and A9 should be infinity but if it is not off scale high, you might have a bridge or a bad connection somewhere.

 

I would assume data lines are fine since you saw 00000 on screen briefly before it crashed. That suggests the data lines are working at certain address range.

[alcruma]

Hi all. Good morning.

 

Wickey: Thanks so much. If I have time this afternoon, I wil try your roms.

 

Kroko: -Yes, I've verified the eprom content BEFORE (all FF) and AFTER burned ( fc /b rom.bin rom2.bin --->no difference found). rom2.bin is a reading after burning eprom.

-No, never try to double the rom. One thing to try.

-Using A12 as /CS? I dont understand. If we stuck /CS to ground, the eprom will be always enabled. A12 (in the eprom)is for selecting the 4K page, and in the console, inverted is for emprom's /CS. Can you explain a little more what you want to do?

-Yes. Absolutely sure. I've put a stick in my pcb signaling the upper side.

 

Nanochess: How can I upload the photos? Simply atached a zip file to a reply?

 

One time more, thanks at all for your help. I fell silly, since its a very easy circuit.

[alcruma]

7800 fan: Hello. I've tested continuity and shorts in all wires, not only in Data lines. In fact, I've rebuid two time the cartridge. The second time, I use a watcher magnifier searching for shorts in solders, but nothing. its perfectly solder.

I always use the info on console's connector found in internet, that says that the +5V is the second pin from the left, and upper side. I've verified this in the console, with a tester, and using the +5, the rest of pins are identified.

Edited March 26, 2015 by alcruma

[+nanochess]

.

 

Nanochess: How can I upload the photos? Simply atached a zip file to a reply?

.

 

 

In the reply box use the "More Reply Options", you'll see below a box to attach files, select your file and click "Attach this file", you can attach several files.

 

Usually the JPG files are attached directly without compressing them with ZIP.

[alcruma]

Hi all.

 

Wickey: Thanks so much for the roms. I´ve tried it and only gets an unsincronized image on tv and a continuous sound. Obviosly, changing the A12..A14 dont change nothing. Are they PAL?

 

OK. Here you can see the photos of the cart.

As I previosly said, you are not going to see much. The wires covers the pcb.

 

Yes, yes, I know. Its not beatiful, nor nice, but I'm 44 old, and my father gives me my first iron solder at teen so, believe me, the solders are good.

 

 

OK, roms, are not the problem, since I tried 12 different and no one works. Has to be a missconnection.

 

In the last photo, you can see what I think is the console's connector, The eprom is wired to meet this schema.

Can you confirm its correct?

 

 

[+nanochess]

It looks like in the fourth picture, the third wire from the left is touching the second wire.

 

Not yet checked your connections (busy at work )

 

Use a multimeter and verify for unwanted connections between pins.

 

I made one of these for 8K some years ago, I had problems with unwanted connections (I've used a too fat wire)

 

http://atariage.com/forums/topic/217250-space-raid-2600/page-4?do=findComment&comment=2858266

http://atariage.com/forums/topic/217250-space-raid-2600/page-4?do=findComment&comment=2858538

[Kroko]

I wanted you to connect the inverted Atari2600 A12 to /OE instead of /CS. A12 of your EEPROM should still be controlled by your switches.

/CS is the chip select.
/OE is output enable.

In principle both do the same thing, but for some chips the timing is different. I have seen /OE being faster than the /CS. But I doubt that this is your issue... I was just running out of ideas ...

You can also check the CS and OE timing in your chip's datasheet

 

>> Using A12 as /CS? I dont understand. If we stuck /CS to ground, the eprom will be always enabled.
>> A12 (in the eprom)is for selecting the 4K page, and in the console, inverted is for emprom's /CS.
>> Can you explain a little more what you want to do?

Edited March 26, 2015 by Kroko

[alcruma]

Ok kroko, now its clean for me. I can try this, just moving two wires...by the way, i'm so sorry for the german children in the plane crash. Today, when I read the news, i couldnt believe what can make we the human.

 

Nanochess, its a optical effect. They arent touching. I've retest with the watcher magnifier and with the tester that are not any short between any two adjacent pin in the eprom.

 

Only left is that my info on consoles conecctor is wrong.

[Kroko]

Your connector looks fine. The blue jumper ? what does it do ? As it is installed in the picture to me it looks as if it pulls down your PGM pin to ground. But it is hard to see. Please confirm you are not pulling this pin down to ground by the jumper! It needs to be on 5V. Can you check that none of your inverter outputs is connected to ground. Your setup doesn't look very clean

[alcruma]

The 3 blue jumper, when placed, connect A12, A13 and A14 to +5v. When NOT in place, the lines are to ground by 1k ohm resistor. PGM only exists in the 2764 and 27128, in 27256 its A14. I take this in mind when testing one or other eprom.

Tested all unused outputs of the 7404, they are open, and its inputs, tied to +5 or ground (wich was more near).

If do you want to see an unclear design, please take a look to the cart of nanochess 3 replys up. I dont khow how can he put that amount of wires there.

[Wickeycolumbus]

Wickey: Thanks so much for the roms. I´ve tried it and only gets an unsincronized image on tv and a continuous sound. Obviosly, changing the A12..A14 dont change nothing. Are they PAL?

 

Yes, they are PAL. Either way though, you should get some type of image on screen. Is the unsynced image recognizable as the game?

[alcruma]

Nop, but could be. I see seven or may be ten times the same patern, and displacing continuosly up in the screen. When i move the game select swith in the console, the image flips a little, moving the game reset switch dont changes nothing. Iam using a modern flat tv with my console, wich dont may be a problem, as its works good with a original cartridge.

[CPUWIZ]

Is it possible that the funky edge connector has pins connected to each other on the circuit board side?

[alcruma]

Hi CPUWIZ

No. They are sanded very deep, and tested with the ohmeter.

Next thing I'm goig to do, is precisely change this board, for another with the edges connector traces a little wider.

then, if not success, I will give up.

[alcruma]

Hi all.

I surrender.

I've change the base PCB, the one with the contacs to the console, and nothing.

There is nothing more to change or to test.

 

This is the only rom that shows something in the TV (test pattern)

 

But unfortunately, unsync

 

The rom PACMAN from wickey:

 

Here you can see the console. clonic Ayostay and soocer cartridge:

 

working perfectly:

 

So, thank you very much for all you have help me, but this dammed thing is going to trash.

 

Best regards.

Alberto.

 

 

[+nanochess]

Not so fast

 

Put a 0.1 uf capacitor between VCC and GND of EPROM.

[alcruma]

Ok, but tomorrow. Today I am tired and angered with this thing.

Thanks for your support.

[+5-11under]

Just brainstorming...

Is the Test Pattern program 2K or 4K?

I see a tantalum capacitor on the board. Is it in the right way? Maybe try ceramic instead?

[alcruma]

Hi all.

The tantalium cap is 10 mf and its well polarized, and the test pattern rom is 4k. You can find it in stella emulator download.

Nanochess: added .1 cap as you suggested, dont works.

Only to do is make a new pc board not using prototype pcbs. May be this chinnese prototype pcb boards arent suitable for high frecuency works, but I doubt.

I would like to try my work in a genuine atari 2600, may be this clonic need something more or less than the original console. It has built in 32 games, so, perhaps his circuitry would need a different circuit.

I dont know.

Edited March 29, 2015 by alcruma

[alcruma]

Hi.

This morning, I'm gone to a flea market. You Know, a market of second hand things, and I 've buyed a nintendo gameboy advance (4 US$), and this sega hand controller (2 US$).

 

its for the sega Genesis console, but it has the 9 pins atari connector, so I thought give it a try.

IT WORKS GREAT.

Has a better (for me) playablity than the squared original atari controllers.

One thing I remember from my youth, when playing atari with my brother, is that, after two hours playing, it hurts the palm of the hand.

So, if you want to preserve the originals, get some of this.

Albert.

[alcruma]

Hi all.

Here is my new printed circuit board for the (damned) home made cartridge.

I've opended my clonic, and I noted that all IC's are CMOS, so I've changed the 74LS04 for one 74HC00. I'm using a gate as inversor, others gates, tied to vcc and ground.

I've changed the design for the eprom's 4K page. Before, the lines were conected to ground via a 1K, now they are coneccted to a Vcc via 4K7, and the blue jumpers will conect them to ground when placed.

All the resistors for the rom´s selection (A12, A13 and A14) and the capacitors are going to be SMD.

Stay tuned.

 

 

[+nanochess]

Extra suggestion for slow EPROMS: connect selection to OE, keep CE to ground.

[alcruma]

Hi all.

New PCB ended and tested for shorts and brocken traces. Its OK.

 

Now populated with their components:

 

Also a new base board.

 

Tomorrow, time for wiring all and test it.

 

I spent some time this afternoon in the hardware forum. I've seen that I'm not the only that made a home cartridge and not be able to make it works.

Its very strange, since the circuit can´t be more simply. Just connect address and data of the eprom and invert A12. All is very well documented in several web pages.

 

Best regards.

Alberto.

[7800fan]

Could have been much simplier but AA store stopped carrying blank 2600 boards sometime ago. I got a few with F4 bankswitching support and a few with no bankswitching. Was going to make multicarts that hold nearly all of the games but then Harmony came out and mine sat in a pile of to-do bin since then.

[alcruma]

7800fan: Would you sell me one of them, in case my design dont works?