Amazon TV won't show signs of life

Here's an Amazon Fire TV Set-Top-Box from 2014 that won't show signs of life when plugged in and I would like to know if it's possible to bring it to such again and where I would have to look for the faulty part.

When connected to a working TV with a working HDMI cable, no signal shows on the TV and no lights at all on the box.

Both the remote and the power-plug work, I checked with another Amazon product and a multimeter respectively. And there does seem to be _some_ voltage on the board, but I'm not sure if I'm measuring correctly and how much voltage I should be able to detect and at what parts on the board.

Is there a serial defect with these boxes?

The one here is not beat up and since I cannot see any faulty parts on the board I wonder why it stays silent.

Can anybody guess what would be the culprit most likely or point me to another community with experts on this one?

Cheers.