3DS green LED lights up briefly?

Have a Nintendo 3ds the initial blue shone, but then with click out went. As a temporary solution, you could angled the hinge 90 degrees, then he went to. After 1 week of use, but this was no longer synonymous.

Screwed on and speaker cable changed because it was demolished, now lights up when you turn on the green LED (next to the upper screen) but no click or shine the blue LED more.

Battery and charger are not in question, since I have already tested (expanded by the friend). Other visible damage can't be seen. (Not happened after a fall)

Does anyone have an idea what the problem could be or a proposed solution?

RESOLVED: I inserted the cable into the holder the wrong way round