Galaxy S3 rebooting over an over, how can I fix it?

[AC Question]

Galaxy S3 rebooting over an over

I know similar questions have been asked before, but my phone is doing something else. I got my Galaxy S3 two years ago but after about 6-10 months it stopped working. In the beginning, it would turn on all the way but would reboot after a few minutes. By the end of the day, it was stuck in a reboot. It makes it to the Samsung logo and will sit there for a while, but instead of turning on all the way, it restarts. After a few days I gave up on fixing it and bought a new phone (Moto G 1st Gen.), but now that phone is starting to go out (only charges upside down). Because I am a college student, I don't have money to go and buy a new phone. I still have my Galaxy S3 and am hoping to fix that while I save up for a new phone. Many posts say to restart in safe mode or factory restart the phone, but since it doesn't turn on far enough to do that, I would like some new ideas.
I am thinking that I need to get the power button replaced, but I am not sure that is the problem since I do have to hold the power button to turn on the phone after pulling and replacing the battery.
Anyway, I would like to have a solution before my Moto G stops charging for good, which based on past experience, is only a few weeks.
Thank you for any responses.

 

[B. Diddy]

Re: Galaxy S3 rebooting over an over

Welcome to Android Central! Have you already tried a new battery? A dying battery could cause that kind of behavior.

 

[enigmadreamer]

Re: Galaxy S3 rebooting over an over

Yes I have, that was the first thing I tried.

 

[B. Diddy]

Re: Galaxy S3 rebooting over an over

Are you able to boot into Recovery following these steps? http://forums.androidcentral.com/sa...ing-into-recovery-mode-galaxy-s2-s3-tab2.html

 

[enigmadreamer]

Re: Galaxy S3 rebooting over an over

No, I did try that originally and wiped my phone totally twice.

 

[B. Diddy]

Sorry for the delay--been busy at my real job!

If you're able to boot into Download (Odin) Mode, then try reinstalling the firmware: http://forums.androidcentral.com/am...w-flash-stock-rom-via-odin-new-interface.html

If this isn't possible, then the next steps would be to bring the phone to a repair shop and have them check out the Power button to see if it needs replaced. If that looks good, then it may be a motherboard problem.