Navitel T500 3G Tablet: Restart Issues during Boot, Power & Battery Troubleshooting

Hello.
I dug out the Navitel T500 tablet from the bottom of the drawer - it stayed there for several months. Now I have a problem with turning it on (there were no problems before)
When you try to turn it on, the NAVITEL logo is displayed and it restarts before booting. Often, holding down the power does not react. When I connect the charger, the battery charging graphic is displayed, then the tablet restarts and recharges the battery - the cycle takes about 5 seconds.
At the start, I thought it was because the battery was too depleted, so I plugged in a powerful charger and left it for 10 hours. Did not help.
So I started to open it and connected the 5V USB directly to the board, omitting the battery. After such a "kick" straight into the heart it turned on, android loaded and started normally. After about 3 minutes, the tablet turned off and everything started again. I have carefully looked through its guts and I find that the PCB has no traces of cold solder, burns, etc. and the battery is not bulged, but my possibilities end there.

Recovery cannot be done either, because right after POWER + Vol UP and selecting the Recovery option, a restart takes place and I go back to the starting point.

(usb cable and charger are ok) :P

What do you think? Hardware or soft?

Edit: Battery voltage is ok.

Then try to upload the firmware to him again.

Does it turn off after 3 minutes with the charger connected?

hello friend
today I was faced with an identical dot to dot problem in exactly the same equipment. And here is the question: was it possible to diagnose and remove the fault = bring the tablet back to life? If so, I would ask for more details about the repair ...

Edition:
the topic was resolved by replacing the battery. The tablet flies like newborn!

I have the same problem.
The only difference is that the tablet required more and more recharging - shorter battery life and just before the final symptom it reset from time to time.
I thought about replacing the battery, but now I can see that it must have fallen deeper.

Edition:
Can someone provide the parameters and dimensions of the battery?

Replace the battery and upload the firmware again.

Start by replacing the battery.

Hello, I wanted to ask if the battery replacement itself, because my friend has the same problem with this tablet, except that the battery has swollen to such an extent that it has opened the tablet completely and only the hourglass is flashing while charging but the tablet does not charge or wants to start, the warranty seals are not visible unless it's the black tape where the battery connector is, so is the battery replacement the only fault in this case, because maybe it would be worth risking a replacement battery because the tablet is pretty cool as an emergency.
Tablet under warranty, but who will believe that the battery is so swollen?
I would try to replace this battery with a new one, but I prefer to ask what you think so that a friend does not drown the money unnecessarily, well, this tablet costs about PLN 250 new, all original charger, etc.
Replace this battery what do you think?
greetings

In my case, replacing the battery did the trick. Nothing else needed to be done. And my symptoms were the same as you describe. First loss of capacity and problems with starting and finally the battery swelled and came out of the housing.

If it is under the warranty, use it.

In fact, the warranty service is the most appropriate behavior here, if there is a warranty, why think about it and lose it as a result.