on the t-con board the leds on the t-con board are on indicating that the basic voltages are ok, I don't see any component of the hot t-con board just all the screen (matrix) filled with colored lines.

Check all the main supply voltages of the LCD matrix on the T-CON board (AVDD, VGH, VGL, VCOM, VCC .....). And try to run the LCD matrix offline.