This is a method for Seiki, and involves cross shipping. If you aren't interested, stop reading.
I've seen the 50 inch 4k TV, and they look almost spot on to Sony's or LG's, at a fraction of the price.

Serial and model:
(50 inch 4k) Model SE50UY04

This is a base serial number that has been used, please change the last 4 digits.
Serial Number: 5030R3310500615



Step 1.
Call up their customer support, tell them the TV won't power on.

Step 2.
They will ask you to email in a proof of purchase, and a serial/model number (see above) They don't verify, so amazon works just fine, as does just a local electronics store receipt.

Step 3.
Call them back after a few hours, they will offer you an advance replacement. This involves putting a full hold on your credit card. If you convince them its urgent enough, ask them if you can ship your unit to them first and get the new unit shipped out when you provide tracking.

Step 4.
They will agree, and tell you to call back with tracking information. Ship out an empty box along the specifications of the box. Normally you can buy a picture box at fedex for around 20 dollars or so, or if you have an old TV box that works fine, just make sure you put a few bricks or rocks in there. You can ask them for a prepaid shipping label, but most of the time they've just asked me to buy it. Its never been more than 30 dollars.

Step 5.
Call them back and provide tracking. They will ship out the TV via UPS ground

Step 6.
Enjoy your new 50" 4k TV


Notes:
Some of you might be able to take this method alternate routes, but I didn't put too much time into it. Enjoy, and message me if you have any questions