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Oooops, never do that again.
Some signals are controlled by Open-Drain circuits; doing that you can fry it...
Use pull-up resistor for such test and disconect signal from its control circuit.
In your case, remove R9704 and connect C9704 with C9723; only pads are there.
This is a short fix; no backlight control anymore.
But you didn't specify if image is present.
Your original problem was probably C9560, which will happen again once the cap has cooled down. Either the GPU got fried or U9600. My vote is on U9600. Did you cover over this with a lot of kapton/aluminum tape during reflow of GPU?