Galaxy S3 4G Multiple Issues

[bonscottmc]

I have a Galaxy S3 4G (GT-I9305T running Android 4.1.2) which has started messing up big time in the last week. Firstly, the network is constantly dropping out with no service, and the forbidden sign is showing in the notification panel. Secondly, at certain times when it does this, the screen will start flickering, and it will restart itself, sometimes several times before it is ok again. Thirdly, the battery charge can be all over the place when these issues take place. I can have say 50% or more battery left and after it restarts it will be on zero, then it dies again until I put it on a charger which in an instant makes the battery charge go back up to whatever percentage it was at before dying. It's like the phone isn't reading the battery charge correctly or something..
One thing I noticed is that when the network drops out and the forbidden sign shows it will give me a 'insert sim card to access network services' message. So I'm guessing it's also failing to read the sim card properly at certain points.

I ran my phone dead twice in a day last weekend and it's only since then that the problems have started. I've done a factory reset but that didn't help at all.

I'm Australian, I'm on the Optus network but my phone is unlocked, and it isn't rooted or doesn't have any custom firmware etc if that helps.

 

[GSDer]

It sure sounds like you're having (at minimum) a battery problem - until you get that issue resolved there's no way to tell what else might be going on. Do you have someone that you can temporarily swap batteries with?

Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk

 

[bonscottmc]

Not at the moment, but I will try another battery when I can. Is there any possibility a bad battery may be causing the other problems?

 

[GSDer]

Is there any possibility a bad battery may be causing the other problems?

If the battery state is all over the place I could easily believe that the phone would be acting wacky.

Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk

 

[bonscottmc]

Ok awesome. If that's the case it will save me having to get the phone sent away for repair. I'll post back as soon as I get my hands on another battery. Thank you

 

[bonscottmc]

Sorry about the slow reply, but I didn't manage to get a new battery and have been managing with it up until last night when it got stuck in the 'boot loop'. I've tried factory resetting, emergency firmware recovery with Kies, and even tried reinstalling a stock firmware with Odin but nothing has helped. Unless you guys have any other ideas I'll have to take it in for repair tomorrow.