I have this old Sony Ericsson G502. I barely used it because it got submerged in water a while ago. I left the bits out to dry, but failed to ever try to turn it on again. I've kept it, and a couple of days ago, I plugged it into a charger. A red light came on at the back of it. I looked it up. The light was solid, indicating it needs time to charge before it can turn on. Had it been blinking, it would've meant battery issues.

Anyway, my problem starts when I unplug it and turn it on.

The phone starts up, and I can hear the tune along with the Sony Logo coming up. Then the side-lights in the screen die. I put in my pin and lock the keypad. When I try to press a key while it's locked, the back-light comes on and I can see the home screen. When I unlock the keypad, the side-lights light up the screen for a fraction of a second, then go off, leaving the screen pitch-black. Is there any D.I.Y way to fix this? I need a temp. phone and I can't really go to get this one fixed just for that.