Here is a simple Guide for build your own USB-Jig,it should gives your Phone a new life when it
doesnt Boot,doesnt recognize from your PC for Odinflash etc.When your Phone is not going on
with it than u have Hardbricked your complete Bootloader and when u have luck the Jtag helps(maybe)
Whats needed:An Resistor with exact-301k ohms
A USB wire with micro USB plug
A lil bit tech knowledge
Insert the plug into the SGY be sure the Phone is not on,because the screen is black and you cant see it.
Release battery to be sure its off and do it back after few seconds.
Just hold the Resistance on Pin 4 + 5 and the download mode(Odinscreen)should start from it self.
When u see the screen with the yello triangle,remove the Resistor and flash your Phone normaly
For better understand how to prepare the your Jig i have addet an Guide with Pictures and text.