2600 cartridge repair

[Duke]

I’d like some advice. I seem to have bad luck with 2600 carts not working. I have three that will not work. Most recently, I was very excited to find Frankenstein’s Monster for a decent price at a retro shop I frequent and it won’t boot up. I cleaned it very well as I always do to my cartridges and even took the board out and polished the pins. Still nothing. How common is this?  I’ve asked other collectors and most say they’ve rarely, or never, had a 2600 game they couldn’t get to work. Is there anything else I can try?  Thanks so much. 
 

Duke

[+Stephen Moss]

You could try re-soldering all the joints, you might have a dry joint somewhere that is prevent in the cart form working.

[Voxel]

Like SM said above you can check the continuity with a multi meter, however the typical fault, such as in your case is the IC has lost its' memory and the game data has become corrupt.  If you take the shielding off you should see an EPROM with a sticker over the window.

 

If you leave one of these games idle for about a decade (sometimes less) the tiny amount of charge held in the memory matrix (capacitors) discharges (eventually).  Games with these IC's need to be played every few years to maintain the charge in the memory matrix.

 

One solution would be to blank the IC and re-flash it.

[+-^CrossBow^-]

19 minutes ago, Voxel said:

Like SM said above you can check the continuity with a multi meter, however the typical fault, such as in your case is the IC has lost its' memory and the game data has become corrupt.  If you take the shielding off you should see an EPROM with a sticker over the window.

 

If you leave one of these games idle for about a decade (sometimes less) the tiny amount of charge held in the memory matrix (capacitors) discharges (eventually).  Games with these IC's need to be played every few years to maintain the charge in the memory matrix.

 

One solution would be to blank the IC and re-flash it.

Pretty sure most 2600 games are using masked roms and not eproms. There are few later releases that did use eproms from Activision and Absolute during the revival of the 2600 in the late 80s. But I'm pretty sure that shield is only for additional interference filtering and that underneath is a masked rom.

 

I'm going to ask a different question?

 

Do you have any games that you are able to get working on your Atari? If so which ones specifically?

 

[Voxel]

2 minutes ago, -^CrossBow^- said:

Pretty sure most 2600 games are using masked roms and not eproms. There are few later releases that did use eproms from Activision and Absolute during the revival of the 2600 in the late 80s. But I'm pretty sure that shield is only for additional interference filtering and that underneath is a masked rom.

He'll find out, should he lift off the shielding.

[+-^CrossBow^-]

1 minute ago, Voxel said:

He'll find out, should he lift off the shielding.

Well, I've lifted that shielding from quite a few of my 2600 games from back in the day and they were still using masked roms. Usually with an eprom cart there will be a small IC in addition to the eprom to allow the eprom to work. Again on later releases that used them you can usually see them at the front of the PCB just behind the contact pins. I know my first copy of Tomcat for the 7800 was an eprom game and I've heard of quite a few others being found over the years but most of them were using masked roms.

 

[Voxel]

Your points are valid.  My thoughts are based on what I'm seeing here.

[ChildOfCv]

1 hour ago, Stephen Moss said:

You could try re-soldering all the joints, you might have a dry joint somewhere that is prevent in the cart form working.

Don't forget the vias either.  Vias are the holes in the board that move a trace from one side to the other.  The holes have a conductor riveted into them, and over time it could possibly lose contact.

1 hour ago, Voxel said:

If you leave one of these games idle for about a decade (sometimes less) the tiny amount of charge held in the memory matrix (capacitors) discharges (eventually).  Games with these IC's need to be played every few years to maintain the charge in the memory matrix.

I've never heard anything about the retention time of an EEPROM being affected by use.  You may be conflating the concept of EEPROM with DRAM.  DRAM uses a matrix of capacitors that must be constantly recharged whether used or not, and must be reprogrammed after read because reads are destructive.  

 

EEPROMs use a floating gate that must be charged or discharged by a high voltage.  The charge on the old EEPROMs will last about 10 years, period.  The manufacturers do not say anything about usage affecting it.

 

Anyway, I have one such game as the OP mentioned, which does not work.  It's CO12035-22, which is apparently Maze Craze.  According to the Atari Master List, it's a 32K ROM.

[Voxel]

1 hour ago, ChildOfCv said:

You may be conflating the concept of EEPROM with DRAM.  DRAM uses a matrix of capacitors that must be constantly recharged whether used or not, and must be reprogrammed after read because reads are destructive.  

Clearly I've mixed the two in my response, thanks for reminding me.

 

1 hour ago, ChildOfCv said:

The charge on the old EEPROMs will last about 10 years, period.

That's what's on my mind if the game data has become corrupt, assuming one of these chips is in the cartridge.

[ChildOfCv]

Yep, so if it's an old game with original EEPROM, it may be in need of a re-burn.  From the way it's described, the EEPROM hasn't gone bad, it just lost its data, and a new programming should fix it.

 

If it's a mask ROM, it could have been anything from deteriorating traces to a lightning strike.

 

Incidentally, I tracked down a datasheet that includes the one used in my cartridge, at least:  MSM2932.  As expected, you have to order them programmed.  For OKI Semiconductor, the procedure was that you shipped them a hex printout of your ROM data.  They digitized it and created a sample of master EPROMs, which were sent back for verification.  Once the OK was given, a mass run of mask ROMs was produced.

 

http://www.bitsavers.org/components/oki/_dataBooks/1982_OKI_Memory_Data_Book.pdf   Page 129

Edited August 31, 2020 by ChildOfCv

[Duke]

Wow, these are some great responses. I really appreciate everyone’s time. I again tried cleaning the contacts one last time, used my multi-meter and checked all the traces and tried it on 4 different Consoles. I’m convinced it’s definitely the chip. So you guys think my best option is to somehow have it reflashed? I guess I’m just looking for my best option to get this cart playable again. Thanks again for all the great advice. 

[ChildOfCv]

34 minutes ago, Duke said:

Wow, these are some great responses. I really appreciate everyone’s time. I again tried cleaning the contacts one last time, used my multi-meter and checked all the traces and tried it on 4 different Consoles. I’m convinced it’s definitely the chip. So you guys think my best option is to somehow have it reflashed? I guess I’m just looking for my best option to get this cart playable again. Thanks again for all the great advice. 

If it's a ROM chip, that won't be an option.  In that case, you'll just need to find an EEPROM and a modern Atari cartridge PCB replacement (and a ROM data dump), and have the game programmed into it.

[slacker]

I had this issue with a copy of Video Chess I picked up on eBay for dirt cheap. The seller guaranteed it worked but it was DOA when it arrived. I have 6 2600s and it didn't work in any of them. I took apart the cart and cleaned the pins as well as re-flowed all the solder joints with no luck. I let the seller know and they refunded me the few bucks I was out for the cart. I ended up picking up another cart and worked fine.

My copy of California Games that I've had since I was a kid used to work fine. Sometime in the past 15 years, the bike track is now bugged out and doesn't work right. There's random corruption when playing that game type (but surprisingly none of the others... the bike track is the best part of the game so it's sort of a bummer). I'm guessing the ROM is deteriorating or something as I know it worked completely fine for many many years before it started to bug out.

[4ever2600]

Do you have a different Atari 2600 system to test the carts on?  Could be the Atari having issues and not the carts... just a thought before you tear apart any rarer cartridges. 

[+-^CrossBow^-]

17 hours ago, 4ever2600 said:

Do you have a different Atari 2600 system to test the carts on?  Could be the Atari having issues and not the carts... just a thought before you tear apart any rarer cartridges. 

Exactly why I asked at the end of my 1st reply if the OP had any games that he can get working on this Atari. Because my thought was also leading to an issue with the system itself and not the games. But I didn't get an answer on that I don't believe?

 

[Duke]

On 9/1/2020 at 5:13 PM, 4ever2600 said:

Do you have a different Atari 2600 system to test the carts on?  Could be the Atari having issues and not the carts... just a thought before you tear apart any rarer cartridges. 

Yes, I’ve tried it on my light Woody, my jr and my 7800. The chip is definitely fried. 

[+-^CrossBow^-]

16 hours ago, Duke said:

Yes, I’ve tried it on my light Woody, my jr and my 7800. The chip is definitely fried. 

Understood. It does happen though rare. I have a Tapper that exhibited the same behaviour. Could never get it to work no matter how much I cleaned it. And since the masked rom on that cart was just a die under a blob of black epoxy, I had no way to very beyond where the traces went under the epoxy blob and all of that tested good. Picked up another Tapper a few years later that worked fine. I might still have that bad Tapper cart somewhere.