Dropped in water. Dried out and charged. Now turns on and off.
I dropped my iPhone in water and pulled it out immediately. I tried drying it off with a towel but it had already been completely submerged and the screen kept cutting in and out. I eventually put it in a bag of rice to dry out any moisture that remained in it and left it overnight. The next day when I turned it back on the black screen with the silver apple came on for about 5 seconds then shut off again for about 10 seconds then back on again. It keeps doing this unless I plug it in to the wall or computer. Then it just has a constant screen of a usb cable with an arrow pointing to the itunes symbol. I have tried connecting it to itunes and restoring it but it only gets so far before it says it can't finish the restoration. I was just wondering if my phone is beyond repair.
I have almost the same problem (although I need to force the 'usb poiting to iTunes' screen by going into rescue mode.
I'm 99% sure that my problem is a bad battery AND a bad/broken power (on/off) switch. I'm going to try cleaning it or if that don't work, replace it. See other posts for more info...
I completely took it apart again. Removed the display assembly (but not separating this), mother board and sync connector. Cleaning everything by blowing clean, compressed air (from a aerosol can) in every nook and cranny and trying to get air in between the mother board and the RF sheilding from all directions, blowing everywhere on the back case and on and around the buttons (that where still in the case) and on all connectors (both on the mother board and on the flex cables).
Then assembled everything again, making 100% sure that all the connectors where correctly seated. Turn it back on and loo and behold! Everything works like a charm!! I can turn it on and off, I can enter DFU mode and it doesn't reboot as soon as I unplug the sync cable!! Dang, I'm a happy camper now!! :D
PS. Just in case this haden't worked, my next attemt would have been to spray/use some 'electronic cleaning solvent'.