Gameboy Battery Replacement Question

[bmoc]

One of my Gameboy games (Donkey Kong) stopped saving games so I ordered some batteries and figured I'd just go ahead and replace the batteries in all of my Gameboy games since they too were pretty old.

I didn't have any trouble replacing the batteries. It was quite easy compared to the composite mod I did on a model 2 Genesis a while back. However something peculiar happened that I was hoping someone could shed some light on.

I replaced the battery in the first game and it cleared the data as expected. I was then able to successfully save new data with the game. Next I replaced the battery in Donkey Kong which had a known dead battery. It began working just fine.

Finally I replaced the battery in Metroid II. It did not lose any data. The saved gamed remained intact. How exactly is that possible? Shouldn't it have cleared the data when the battery was removed?

[Hobie-wan]

If the old battery wasn't completely dead and you swapped in the new one fast enough, that's possible. Memory chips don't lose everything the instant power is removed, it kinda fades. Some memory chips fade slower than others. There are crazy ass hacks where people have turned off a computer, blasted the memory chips with cold (say canned air upside down), popped them out, stuck them in a device hooked to another computer, then applied power and read information off them to them.

[bryan_65]

Kinda like how people swap the batteries on a CPS 2 game before it dies. You have to do it in time before the game suicides.

[bmoc]

Interesting. I didn't think that I swapped them out all that quickly. I took my time because I had to trim some metal off the solder tabs because they were a bit long. Good to know though. Thanks for the replies!