Mario bros 7800 cart prob

[Sapicco]

So I recently came up on a loose cart. When I pop it in, I get to the main screen, and it gets stuck. Controllers don't work and there is a constant sound just going. Seems frozen to some degree. Anyone have any ideas how I can make this work properly?

[+save2600]

Try cleaning the heck out of the cartridge slot on the Atari and the edge connector on the game itself.

[Sapicco]

Thanks! Hope it works. What's the easiest way to clean both? I need a "dummies guide to clean for beginner gamers"

[Sapicco]

Found a how-to on this site, will give it a try!

[+DrVenkman]

Thanks! Hope it works. What's the easiest way to clean both? I need a "dummies guide to clean for beginner gamers"

 

For the cartridge, use 72% or better isopropyl alcohol and cotton pads or swaps, and scrub the heck out of the contacts. Use as much force as you need to get them shiny and bare again. They should gleam.

The cartridge slot on the 7800 is a lot tougher to clean. If you're comfortable taking the unit apart, you should remove the cartridge slot guide (held in place with tabs through holes in the PCB and in some early units, also with small screws). Then you can work the contacts with something small like an old toothbrush (again soaked in a strong alcohol or electrical contact cleaner). I've also heard of people using a folded-over piece of card stock like a business card to rub the contacts. While you've got the thing apart, you might also use something slender like a dental pick, a small nail or a toothpick to work the metal tabs of the contacts a bit tighter - they work loose over the years and can make some games iffy in terms of playability.

[Sapicco]

Ok, so I gave the qtip and isopropyl a try this morning. I actually got past the main screen by pressing buttons really fast as it was loading up. But, still froze as soon as I got to the first screen. Oh well, I'll keep trying to clean it better before I give up. Not comfortable taking the console apart, but maybe in the future if problems occur with more carts.

[SIO2]

If the console plays other games fine, I would concentrate more on cleaning the cart.

 

If the cart is super super bad, I have used a plastic type scouring pad (like scotch brite) gently on the cart contacts. I used a wooden craft stick to press gently on the scouring pad while running the pad over the contacts. This is a second to last resort because it can scratch the inside of the plastic shell or pull off a contact (be careful).

 

Last resort would be open the cart so you can work the contacts well with scouring pad. But opening Atari carts usually means damaged label since many have a screw hidden under the label.

Edited April 6, 2015 by SIO2

[7800]

Get the 0000 fine steel wool and use a little bit of that on the contacts. THEN, clean with alcohol. After that, you can apply alcohol on the contacts and push the cart in and out of the console slot, that will help clean the slot. Let everything dry for a minute or two then see if it helped.

[Sapicco]

I will keep scrubbing and cleaning. I've tested about 50 games, mostly 2600 games and no issues. Same problem happening with my 7800 donkey kong cart. So weird.

[phoenixdownita]

As I stated elsewhere I had to mod my Robotron2084 cart and add a 200 ohm resistor series the VCC pin or else it would randomly crash.

Now Robotron is a 32K and some original 32K Atari PCB already had such resistor in series, while your issues come from 48K games.

I do not know if Atari used two mask roms (32K + 16K) or one 64K with 16K unused, but it is possible your carts may need such resistor in series.

 

Repeat: I only had the random crashes issue on Robotron, no other games had issue with my 7800, once I modded the cart no more issues, ever.

Unfortunately there's no easy way to test the theory because to put that 200 ohm resistor series the VCC you either need a cart extender or to open up the cart and mod it as I did .... likely none of which is an option for you.

 

If I were you I'd try to repurchase one of the trouble games and if that copy works resell yours, there's nothing wrong with it per se likely it'll work fine on a lot of other 7800, just not yours. If a second copy does not work then maybe your 7800 puts out a barely in spec VCC to the cart and may need servicing (maybe a new 7805).

[Sapicco]

Ok, just bought a second copy of Mario bros. Just an update, tested more 7800 carts today. One on one basketball, real sports baseball, and robotron. Can't get robotron off the main screen. Basketball and baseball almost work, but crash as soon as I throw a pitch or start a basketball game. Other 7800 carts such as pole position, joust, choplifter, xevious, ballblazer, asteroids, centipede, hat trick, and karateka (really crappy game btw)are all working fine. I don't know if the other games require more "power" to work and my system is faulty and needs servicing as Phoenix suggested. I guess I'll see when the new mario bros arrives.

[Sapicco]

Today I was able to give up two base hits in the top of the first inning before it cransed in real sport baseball! Progress...

[Sapicco]

For those following along, just got a new copy of Mario bros in the mail. Same issue, crashes at the title screen. I am starting to think my 7800 is defective. It only plays 2600 games and only my 7800 games that I don't want to play as much as the others. I wish I knew someone who had a 7800 to test my games to see if they work on another console.

[+DrVenkman]

For those following along, just got a new copy of Mario bros in the mail. Same issue, crashes at the title screen. I am starting to think my 7800 is defective. It only plays 2600 games and only my 7800 games that I don't want to play as much as the others. I wish I knew someone who had a 7800 to test my games to see if they work on another console.

 

Two things - first, as I suggested above, take it apart and gently bend the cartridge slot pins a bit with a dental pick or wooden toothpick to improve contact pressure - 7800 games seem much more sensitive to marginal connections than 2600 games, at least in my AT-84 serial number machine.

 

Second, it's possible you have a bad MARIA chip in your machine. Fortunately, replacements are still available at Best Electronics for not that much money, and as far as I know, 7800 motherboards are all socketed so it's not hard to replace. Of course you could just to remove and reseat all the IC's anyway to see if that helps - there's a 6502C in there, a MARIA, TIA, OS ROM and 2 x 16 kilobit SRAM chips.

 

You say 2600 games play okay so there's not much chance there's anything wrong with the 6502C or TIA, or probably the OS. But bad SRAM, a bad MARIA or possibly a bad OS could all cause trouble with 7800 games, in addition to a possible bad connection at the cart slot.

Edited April 12, 2015 by DrVenkman

[+-^CrossBow^-]

Not all 7800s have socketed chips. In fact only the early released ones have them just fyi.

[Sapicco]

Donkey kong crashes when the title screen loads

baseball (2 nib), crash after the first pitch

Mario bros (2), crash when title screen loads

tower toppler ( nib, it loads but each time the frog exits the spaceship it just keeps cycling through all the "towers", with that annpoying music

robotron can't get Off the title screen

one on one crashes when I start a game , demo mode plays though.

 

Dig dug, pole position, shoplifter, xevious, hat trick, katateka , ballblazer, centipede joust, work.

 

Since I really have no idea what/how to do what DrVenkman is saying, does anyone know someone in the Boston area who can fix my machine?

 

Othwerwise, I will have to just buy a new one off eBay.

[Sapicco]

Tower toppled was a difficulty switch issue! Too bad the rest arent.

[Sapicco]

Finally got a new 7800. Mario bros and Donkey Kong working just fine. Anyone know what could have been the problem with 7800 console 1? I may need to hire someone to fix it for me.