Not reading DS cartridges.

I don't know what generation my DS is, I know it's one from before the lite and 3ds, but it won't read ds games anymore. It use to run them, then it became a craps shoot, now they won't read at all. I'm a good hand with a soldering iron and I hoping I just need to fix some connections, but I'd rather get a definite answer before I go poking around.