hello. i have 2 GBA and one of them have weirdly loud speaker noise. it is low frequency noise, and weirdly its loud regardless volume! even i turn volume completely off, it's still there and static. loudness of the noise doesn't louder when i turn volume higher. same when using earphones. this time i don't know why causes the problem, but here's my fix : (picture from Ozito) see right side above the volume. there is AMP AGB IR3R60N sound amplifier chip which very little known. using some wire, put a medium size capacitor (i used spare 16V 100uF) to second left leg(description below) and gnd. about the leg, AMP AGB has 18 legs(9 of each side), but mother board has 20 leg holders(10 of each). since chip aligned right side, first holding point doesn't soldered anything(NC) and second point soldered first leg of sound chip. that's the one. i recommend solder the leg(2nd) with NC(1st) together. it will be easier and hold the wire firmly. now it doesn't have any noise even i put my ear to speaker. even quieter than normal one. if you bother noise, try this. FYI : AMP AGB also used on GBA SP too, so if you have same problem with SP, it will be works either.