Why do old game carts corrode even when kept in good condition?

[blueagent004]

why do some old game carts have corrosion and rusting on the components of the PCB board even though they were well-kept and have never come into contact with water before?

i have a couple of old game carts from the early 1990s that have never been opened up before, i've decided to check on them and apparently the game carts now have alot of rusting developed inside of them. its not like the internal battery or capacitor has leaked all over the board or anything like that; those were fine as they are. And i've never dropped the game carts in water before or spilled anything on them. in other words, the game carts have always been kept in my old toy box cleanly and neatly for the past 20 years.

so my question is: Why did some of my old game carts corroded/rusted on the inside even though they were kept in good condition?

[source]

MORE INFO:
i think this photo depicts my problem more accurately, basically the metallic legs of the ROM chips have corroded on my game carts.

thanks for the help!

 

[Clydefrosch]

i suppose lots of humidity where they were produced and packaged? locking in that humidity? and packaging probably wasn't perfect either

 

[blueagent004]

well its fairly humid here where i live, most of the time its 30 degrees Celsius all year round, and the game carts were stored in the storeroom without air conditioning, could this be the reason why?

 

[FAST6191]

More with the long term storage/failures of electronics thing? We are going to have to put these all in a big thread or something one day if this keeps up.

Anyway strictly speaking rust is a form of iron oxide, and corrosion is different to oxidation which is probably what you are seeing, unless a battery leaked or you stored it in a more marine like environment (and it is not like many places in Hong Kong are far from the sea) in which case corrosion is an option. Most people won't make the distinction but this is one of the very few things in the world I know anything about. For an added bonus you might even get to see some creep, and when that combines with oxidation it can be fun -- even at room temperature most things called solder are way above half their melting temperature and thus open to the failure mode known as creep.

Steel/iron, albeit often coated, was used often enough in chips of that vintage (mainly as it is easy enough to solder to compared to the alternatives) but the traces themselves are more likely copper. The solder used to bind it all might well have still been glorious full fat leaded solder rather than this awful silver based stuff thrust upon the world since then, lead does oxidise though and its passivation is not perfect.

I shall spare you my metallurgical ramblings though.

Short version though is while water can seriously increase speeds and exacerbate problems associated with oxidation and corrosion the air alone does still contain oxygen. Most designers of the PCBs even if they even knew of such things* were concerned with electrical stuff, and the default PCB manufacture methods will be fine for things stored in a nice household type condition for 5-10 years, or about the time any kind of warranty really applies for.

*most PCB designers are concerned with getting the electronics sorted, more traditional areas of engineering are then of far less concern. Or if you prefer see why you often see people with dodgy charge connectors.

 

[izy]

well its fairly humid here where i live, most of the time its 30 degrees Celsius all year round, and the game carts were stored in the storeroom without air conditioning, could this be the reason why?

More with the long term storage/failures of electronics thing? We are going to have to put these all in a big thread or something one day if this keeps up.

Anyway strictly speaking rust is a form of iron oxide, and corrosion is different to oxidation which is probably what you are seeing, unless a battery leaked or you stored it in a more marine like environment (and it is not like many places in Hong Kong are far from the sea) in which case corrosion is an option. Most people won't make the distinction but this is one of the very few things in the world I know anything about. For an added bonus you might even get to see some creep, and when that combines with oxidation it can be fun -- even at room temperature most things called solder are way above half their melting temperature and thus open to the failure mode known as creep.

Steel/iron, albeit often coated, was used often enough in chips of that vintage (mainly as it is easy enough to solder to compared to the alternatives) but the traces themselves are more likely copper. The solder used to bind it all might well have still been glorious full fat leaded solder rather than this awful silver based stuff thrust upon the world since then, lead does oxidise though and its passivation is not perfect.

I shall spare you my metallurgical ramblings though.

Short version though is while water can seriously increase speeds and exacerbate problems associated with oxidation and corrosion the air alone does still contain oxygen. Most designers of the PCBs even if they even knew of such things* were concerned with electrical stuff, and the default PCB manufacture methods will be fine for things stored in a nice household type condition for 5-10 years, or about the time any kind of warranty really applies for.

*most PCB designers are concerned with getting the electronics sorted, more traditional areas of engineering are then of far less concern. Or if you prefer see why you often see people with dodgy charge connectors.

tl;dr oxidation is bad
Actual answer because his ramblings actually didnt reply to your question.


"fine for things stored in a nice household type condition for 5-10 years, or about the time any kind of warranty really applies for."

Yes living in a largely humid area will contribute heavily to your electronics damage
And sotring in non typical household conditions + the fact its about 15 years + will have that effect

 

[blueagent004]

Anyway strictly speaking rust is a form of iron oxide, and corrosion is different to oxidation which is probably what you are seeing, unless a battery leaked or you stored it in a more marine like environment (and it is not like many places in Hong Kong are far from the sea) in which case corrosion is an option.

thank you so much for sharing your wealth of knowledge on this with us, FAST6191 ! and you're right, it could just be oxidation, as i used to live in the seaside area back when i first bought these game carts. actually now that i've examined one of the carts more closely, there appears to be a dried fungus on the exterior of the cart, close to where the contacts are to be precise. the fungus itself look like a blob of dried toothpaste, and it definitely wasn't there before the last time i put those carts into storage years ago.

Yes living in a largely humid area will contribute heavily to your electronics damage
And sotring in non typical household conditions + the fact its about 15 years + will have that effect

thanks so much for lettiong me know! guess i should've stored them in the living room where there is constant air conditioning. oh well...