Galaxy Tab 4 tablet crashed, now won't boot (power supply issue?)

Samsung Galaxy Tab 4 8.0, model # SM-T337V

This is a tablet I was attempting to fix for a family member (who almost certainly does not have the correct charger).

The original issue with the tablet was a blinking screen followed by a reboot loop - but this was not an issue when the tablet was plugged into the wall with my charger.

My charger is a Samsung brand, but intended for a cellphone, not a tablet. (Model # ETA3U30JBE)

I replaced the original battery (EB-BT330FBU) with a EB-BT330FBE.

After the new battery, the issue was resolved for about 2 weeks (nearly constant usage). Suddenly, while turned on (and plugged in - with the aforementioned charger) the tablet clicked off, vibrated briefly, and shut off completely.

The tablet did not respond at all, plugged in or not, until I put the original battery back in (EB-BT330FBU). After this, the tablet responded only when plugged in.

Now it shows the charging animation (battery silhouette with percentage of charge) after being plugged in. When I attempt to boot, it shows the bootup logo, briefly vibrates, and shuts off (doesn't reboot), and goes back to the charging animation.

I put the replacement battery back in and the result is the same.

I used another (generic) phone charger and the bootup procedure got a split-second further along (to the point where the Samsung logo animation begins, briefly, then shuts off).

So it seems like the problem is related to having an inadequate charger. For some reason I can't find the specs for what this tablet needs for a charge.

Please let me know what you think the issue is, whether I'm right or wrong. Thanks for your help.