This TV turns on and off but with no backlight. Sonys typically will flash a blink code but not in this model. Disconnecting the backlight connector has the same behaviour and no blink code. I was able to power on one out of the four banks of LEDs with my LED tester to confirm the TV had video when turned on. Each of the 4 banks read a little different with my LED tester with the expected voltage 6V x 29 LEDs = 174V

Panel number is LTY550HJ04. Research indicates the LJ64-03774A is the part number for the LED strips (SLED 2012SLS55 7030 58 R & L with 5 pin connector) . I have ordered the strips and will confirm the part once I receive it.

Update: Strips arrived and the old strips had lots of bad LEDs. During disassembly a small piece of tape floated onto the plastic diffuser and the glue residue caused a bright glow. I was able to remove it with acetone.