Help Random Restarts & 'Sensitive' Power Button

[GoonerKing]

I have the International version (GT-I9000). A few months ago I had the OTA notification for the 4.3 update. The update failed and when rebooting the phone, it only booted to the blue Samsung screen. A factory reset didn't work so I took it to a repair shop. They reflashed my phone and updated to 4.3. My phone was mostly fine for a while, but now, seemingly randomly, my phone will suddenly turn itself off while I'm using it, when it's sat on my desk/arm of the chair etc.
Sometimes it'll start up straight away and boot to the lock screen. Sometimes it gets stuck in a loop at the white Samsung galaxy S3 screen. Now and then, when it boots to the lock screen and I unlock it, the background has defaulted to the stock screen, and the message 'Unfortunately TouchWiz has stopped.'
The screen goes black for a couple of seconds and then everythings fine. Also, I'm not sure it's related, but the power button seems super sensitive. I only have to lightly brush the button or the casing around the button and the power button appears, or the screen locks.

I have already tried a factory reset, and booting the phone into safe-mode.

I think it's something to do with the power button/battery, but I've also read forum posts on here and in other places, about apps, the OS itself and hardware.

It's really really annoying!!

Anyone help?

 

[Rukbat]

Sounds like an almost-shorted power switch. If you hold the power button in for a few minutes you'll see some of what you're seeing. Random power off can be a bad battery. The boot loop (stuck at the logo) usually doesn't hppen from bad battery, but it's possible, but more probable with a constantly on power switch.

"Also, I'm not sure it's related, but the power button seems super sensitive. I only have to lightly brush the button or the casing around the button and the power button appears, or the screen locks." It's related to the fact that the power switch is probably intermittently shorting. (The "switch" is a springy piece of metal held away from a contact by its springiness. If it gets less springy (fatigue, heat, defect in manufacture), it makes contact when you make any sort of vibration in the phone, like touching it.

You could have two problems, bad battery and bad switch. The battery is a cheap fix - they're about $15. (And it never hurts to carry a spare charged battery with you - just make sure it's in a plastic bag or in a pocket with nothing metallic. There's enough power in there to weld a few keys together.)

The switch is cheap - less than a buck retail. Having one replaced will cost about as much as the battery. (Check eBay.) Still, the phone is worth putting $30 into it.

The background reverting and the TouchWiz stopping sound like some of the normal S3 4.3 update bugs. Ask the repair shop to reflash it to see if a reflash fixes those problems. (Sometimes it takes 2 or 3 reflashes before everything settles down, but the shop doesn't spend as much time with your phone as you do, so sometimes they don't notice the smaller problems. [Another S3 4.3 upgrade bug is that the phone bricks - that they would have noticed.])

 

[GoonerKing]

Thanks Rukbat,

Thing is, sometimes the power button is fine, sometimes it's not, seeing as I've only got a couple of months left on my contract I can live with that, will probably invest in a new battery though.