Galaxy Tab 3 (refurb) bricked -- battery disconnect not helping

[Tardovski]

So my Tab 3 8.0 died on me late in the winter. I'd set it aside and just got back to trying to resuscitate it the past few days.

Nothing traumatic happened immediately before it died on me. It'd been dropped a few times in a hard case but no visible damage or immediate malfunctions.

Symptoms: Won't power up. It DOES have some power though. If I press the power or home buttons or plug it in the backlight will come on. No load screen, no logo, nothing at all, but just the dim glow and the menu/back lights will flash briefly. The backlight will cycle on for maybe 10 or 20 seconds, then off. It will keep doing this for quite a while once it starts, maybe a half hour.

I've tried the power button, power+vol up, power+home, leaving it to charge overnight, USB charging, nothing in the SD slot, and now finally I cracked the case and have tried disconnecting the battery (up to twenty minutes). No dice. The only change is that a couple of times after dis/reconnecting the battery and trying the power button again it gave a few of the bicycle bell rings, in no particular pattern and several times randomly over the course of a few minutes. Nothing on the screen and no other behavior.

Does any of this sound familiar? I've tried searching but the battery disconnect seems to be the universal fix. Since that doesn't work I've run out of ideas.

 

[Rukbat]

Plug the charger in. Let it sit for 24 hours. (Letting a lithium battery sit for months usually drains the battery down to almost nothing. The first hour or so of charging won't be putting much charge into the battery. So just let it charge for 24 hours.) If it comes back, don't recharge it until the tab tells you to. Then turn it off and fully charge it. Do 3 charge/use cycles.

If even 24 hours of charging doesn't give you much, you probably need a new battery. (If you can, measure the voltage at the plug pins. It's probably down near 3 Volts or less.

Read The Care and Feeding of Lithium Polymer Batteries.

 

[Tardovski]

When it had first died I tried letting it charge for a couple days and the behavior was the same. There hadn't been any issues with battery life beforehand. Even unplugged the backlight cycling behavior will still be there, even after it's been unplugged for days. And the recharging symbol doesn't come up on the screen, just the backlight glow.

FWIW, just tapped the power button while it's still plugged in and got another flurry of bell sounds. I'll try leaving it plugged in through tonight and mess with it some more this weekend.

 

[Beut]

No load screen, no logo, nothing at all, but just the dim glow and the menu/back lights will flash briefly.

.

Based on your description, the LCD is dead. One easy way to verify it is using a HDMI adapter, and connect your tablet to a TV which has HDMI port.
If your tablet is working except the black screen then the display should show on the TV normally. Full LCD assembly only costs around $70 to $80 if you know how to replace it. Otherwise, sell it for parts and buy a new or used one, used one may be around $100 .

If you can see the display on TV, try to open the rear cover and disconnect the LCD cable and reconnect it, but the chance of loose LCD cable is rare unless you drop it somehow, but give it a try anyway. A working tablet with a black screen can recognize by the sound of the starting screen or something run in the background.