Hobie-wan wrote:Argh, I keep forgetting to come back and make it into a guide.
In any case, look at the back of your GG. It should have something that specifies the voltage, polarity, and amperage. The wall spits out Alternating current wish has no polarity since the power flips directions back and forth. A US NES power brick puts out AC and I think some random old devices have bricks that do it too, but pretty much everything has a brick that spits out DC. Direct current goes in one direction, so it has a + and - side and most of the time the tip or hole in the end of the part that connects to your system is negative and the outer larger surface of it will be positive. This is the negative center and positive outside symbol you'll see on power bricks and the power information panel on devices.
So if the back of the GG says 9V DC 850mA with a +(•- then you need a brick with the same sized plug that has matching info printed on it. The mA/A bit can be higher on the brick than the device but everything else should match.
My GG says DC 9V 3W but I cant spot an ampage. I dont see a symbol like the one you've drawn in your comment?