I seem to be having an awful time attenuating some high pitched noise on one of my DMG-001's. I can hear it on all outputs - it is loudest on the speaker, followed by the headphone out, followed by the Pro-Sound but it's loud enough to be distracting on all of them. Changing the volume knob doesn't help - the noise is constant. The only time there is no noise is right after the "Nintendo" screen when it first loads the ROM. Other than that, music or no music, it's there. I tried giving it a cap kit today and while it may have helped a bit, it didn't solve the problem.
I have another DMG-CPU-06 that fares much better. It does have a high pitched noise but is not near as pronounced. So I tried mixing and matching and determined that much of the problem lies with the LCD board. The one causing me more problems does have an LED backlit mod - could that potentially have something to do with it?
Otherwise it has me a bit baffled...anyone else run into this with some suggestions on what to do?