I think it's lcd with touch screen connection problem or not working touch screen/lcd . I has about 5 phones in this month (7560 & 7562) with broken lcd or touch screen and some of them after replacement was working, some not. And I changed again touch screen/lcd to new one, then I got them working. After that I've checked one of working phone, just disconnected touch screen from lcd a got boot loop. When I connected touch screen back to lcd, phone booted normally. So you have to wait for a new digitizer and then I hope your problem will be solved.
SGS i9505 16Gb Black Mist / WanamLite XXUBMGA V1.4 + Xposed 2.1.4 + WanamXposed 1.2.0 @ Adam kernel v1.5