Hacking Fixing lifted copper pad on flash cart

[Lemmy Koopa]

So I replaced the battery on a flash cart. All good. Later that day, I noticed the saves weren't working anymore.

I opened it up to discover the copper pad for Negative for the battery was lifted off the board.

After an hour of fucking around I've discovered that the trace for the copper pad is actually underneath where it lied.

The copper pad is broken.

What can I do to repair this? Anyone good with soldering and PCB stuff?

Right now I managed to solder the battery to the trace, but obviously that's not going to hold under stress.

 

[DinohScene]

You could just do a trace repair.
Solder a small wire between the trace and the battery.

 

[FAST6191]

If it was just lifted then you can glue it back down. If the thing is lifted and snapped then if you can glue it back down then make sure it still connects (solder, conductive ink if you are feeling rich, carbon/graphite from a pencil if you are cheap -- if it conducts well enough then you are good). If not then either solder it to the trace or find where it goes, hopefully you have not wiped out any other bonds or you get to remake those as well, and solder is there instead.

 

[Lemmy Koopa]

If it was just lifted then you can glue it back down. If the thing is lifted and snapped then if you can glue it back down then make sure it still connects (solder, conductive ink if you are feeling rich, carbon/graphite from a pencil if you are cheap -- if it conducts well enough then you are good). If not then either solder it to the trace or find where it goes, hopefully you have not wiped out any other bonds or you get to remake those as well, and solder is there instead.

The copper lifted and broke. I'll probably have to replace the pad now.

As of now, I've found the trace under the pad after cleaning it with contact cleaner and soldered the battery to it, but I'm not sure if it'll be strong enough to not snap off.

 

[Lemmy Koopa]

Definitely not strong enough, but, it seems the best result I'm getting is cleaning where the pad was thoroughly with contact cleaner, and then I can see this little silver dot which I believe is the trace, in the middle of where the pad was. I put solder on the battery terminal and it seems to make the best connection, though ironically it's not connected.

So now, it's kind of like a contact pin, more or less, and I put sticky felt on the shell to press the battery's negative onto the trace and it seems to be working fine now.

Tried lifting the shell up a bit and other minor stress tests but the battery never seems to get disconnected.
Since it's working, it's best to say don't fix it if it's not broken, I suppose.


Next time I have to replace the dead battery, I might try to glue a solder tab down on the trace to replace the missing pad.

Thank you for all your input.

 

[romanaOne]

Is there any kind of tiny battery holder for CR1616 that would fit in a GBA cart? (I saw something over at Adafruit for their Timesquare DIY watch kit that holds CR2032, which is too big.) I just fixed a Pokemon Emerald (finally got a legit one!) and thought it was a bit fiddly. I could have done some real damage with that soldering iron and probably will in future repairs as my hands get less steady and eyesight gets worse. It sure would be handy to be able to shoehorn in some kind of socket to hold batteries in my old GB(A) carts.

 

[Lemmy Koopa]

It would be nice, but I doubt it. For future battery exchange, I think I might just solder on a few short wires and just solder to that for now on. I don't know why the fuck the pad lifted off.

The only thing I can think of, is maybe I soldered the battery too close and when I put the shell back on, it was pushed flat and the battery lifted that end.
Either that, or the pad was bad and just fell off from trying to resolder it.

Either way, it's working now via contact, like a pin, and no force seems to be making it loose or anything, so I'm good for now.

 

[Lemmy Koopa]

Just an informative update on this thread's situation.

I've had to do tricks over and over to try to get a good connection on the battery. Eventually it would disconnect over time though. The trace was too small to solder to without the solder breaking off.

I've tried just having the 2 points touch so it reduced stress on the trace without the solder snapping off. This worked decently for a while, but then it got more and more frustrating as any big movement to the cart's shell would disconnect the connection and cause the RTC and SRAM to wipe out.


Today, I've noticed that the trace was surprisingly stronger than it was before, so I tried soldering a wire leading off the trace to the battery's terminal. The wire should add plenty of buffer for any stress movement put on the cart, and it's working great now.

Hopefully it's all fixed now, though I don't want to jinx myself.

If anyone tried replacing batteries in a flash cart, remember to make it as flush as possible in the case so there's no stress on the solder points.