Troubleshooting Kindle 4: Motherboard works, screen is blank

[Darthagnon]

Following my previous issues with my Kindle 4, my mum happened to pass me a non-functional Kindle 4 for spare parts. My original is a ship of Theseus, but working fine, so I've now got a spare to play with.

It charges, powers on, and I even dumped the books that were on it (a bunch of sci-fi omnibuses, much better than the usual teen romance rubbish I've found on old Kindles). However, the screen is blank and displays nothing. It appears to be undamaged, no marks anywhere.

I've opened it up, but no clues there. Does anyone here know where I should look on the circuit board for troubleshooting this? I'm guessing the motherboard is generally fine, as it still boots, charges, connects to USB and read/writes. Replacing the screen is likely not worth it, but as it is quite nice and unscratched, I'd like to save it from ewaste if I can.

[axu2]

Amazon takes broken Kindles for trade-in for 20% off on a new Kindle.

[Darthagnon]

While playing with a broken donor Kindle 4 I got, I thought, "Why don't I connect the battery to this blank Kindle 4?" So, I took the back off both, and because the batteries were still glued in, I made the beast with ~~two backs~~ two fronts by connecting up the (good) donor battery to the blank Kindle 4. It booted. So I connected back its original battery and it's been working fine to this day A story with a happy ending, unlike Othello.

[jackm8]

Glad you made it working. So the problem was a faulty battery on that one?