Tablet resetting and shutting down

[Devriezz]

For some time now my non-rooted tab s 10.5 is randomly shutting down or rebooting. This happens 'out of the blue' so no warnings. Sometimes it happens within a minute of starting, but other times i can use it for hours or it will even continue to work for a whole day before it starts again.
At first i thought that it had something to do with the 6.0.1 update that was installed some time ago so i went back to android 5 official software but got the same results. The tablet then updated to 6.0.1 again but same results. Before installing these updates i did a hard reset to avoid having any old data left on the tablet. Also wiping cache partition did not help.
After reading some posts on this and other forums i turned on power saving and that helps a bit, i can use it longer without the resetting or rebooting. If i turn it off again i can wait for it to reset, meaning usually within the hour. Sometimes it happens several times after you just started the tablet, like it has something to do with the processor having too much to do.
The tablet is two years old, anyone having experience with this problem ? Maybe it is the battery but i hate to spend 40 euros if it is something else.

 

[B. Diddy]

Welcome to Android Central! This kind of thing can be tricky to diagnose, especially if it's due to instability caused by a 3rd party app. Try booting into Safe Mode and using it that way for a while. If it never shuts down or restarts unexpectedly in Safe Mode, then something you installed is probably the culprit. The challenge is to figure out which app, which may involve uninstalling apps one by one until the problem goes away.

 

[Devriezz]

Thanks. I already tried this but as explained this sometimes does not happen for some time and in safe mode there is not much to do with the tablet. It is hard to stress out the system. It could be some app, but it happens only in mail and some games i have been playing for over a year now. It is really random when it resets or shuts down. That is why i was looking for something in the hardware but there is very little to find online on this.

 

[Devriezz]

I decided to order a new battery and just replaced it but the tablet had the same problem again after about half an hour. Bummer.

 

[Who884l5]

You can use the pre-installed apps on the tablet. Yout7be is usually installed or go on the internet. Its one of the few ways to check if apps are the problem.

 

[Devriezz]

After the battery i replaced the charging dock whicht was not too expensive so i thought to give it a go but eveything still the same.

Now i think more in the lines of overheating. When playing a game like HayDay the average temp is 72 degrees celsius which seems quite high to me after maybe 5 minutes playing. Any ideas on that ? The tables has the Exynos 5420 processor, i that known for overheating ?

I used a CPU temparature app form the Play Store.

 

[B. Diddy]

72 deg Celsius is pretty darned high -- that's 161 deg F. Does it actually feel that hot? If so, then I'd suspect some problem with the motherboard.
The only other thing I can think of would be a corrupt SD card (if applicable), so if you have a card inserted, go to Settings>Storage​, Unmount it, and remove it. Now see if the problem persists.

 

[Devriezz]

No Sd card in the tablet, the 72 celsius is only average. It will go over 80 regularly. I might look to find the processor, is this cooled like a desktop processor with some hear spreader ? Time for some open heart surgery.

 

[B. Diddy]

But does it actually feel like it's getting as high as 160 deg F? There might also be a faulty temp sensor.

 

[Devriezz]

Yes it does, and how ! When I remove the back cover and touch the metal plate on the left (I guess that's where the processor lives) with the skin of the top of a finger I can hold it there a maximum of 5 seconds before it's just too warm.

 

[B. Diddy]

You've already done the main things I'd try, short of bringing it to a repair shop. They might recommend replacing the whole motherboard, which may not be worth it.

 

[Devriezz]

I decided to open the tablet once more but could see or find nothing special. In the end i unhooked every connection in the tablet end pushed it back in ( you know, the small square connectors you can pull out with a small tool). After that i put the thing back together.
Now for the past 24 hours the tablet has been running without a problem, even without the power saving option turned on.
Hopefully it will keep working, so far so good.

 

[B. Diddy]

Nice job, McGyver! I'll keep my fingers crossed for you.