My son have a PSP Phat that is plugged on his AC Adaptor but sometimes when he leave it alone he light up on his own. Without anyone being nearby. My son dropped his PSP Phat yesterday and it started doing this today. Any idea what could be the cause of the PSP lighting up on his own.

I have 3 theories but dont know if they are plausible.

1) The battery seem a bit loose so it could be possible that sometimes the contact get off and on.

2) It might be the power up button that have a problem.

3) Someone told me it might be because the battery is weak and need to be replaced.

So what do you guys think.