Are you suggesting swapping individual LEDs between prime and hydra?
It is possible that flickering is caused by a bad LED, but not guaranteed as seen in one of my repairs:
Some of my previous repairs: https://www.reef2reef.com/threads/radion-xr30-complete-no-light-repair.792711/ https://www.reef2reef.com/threads/radion-xr15-doesnt-power-on-due-to-corrosion-repair.809136/ https://www.reef2reef.com/threads/another-attempt-at-fixing-apex-eb832.804717/ And as always...
www.reef2reef.com
Replacing individual LEDs on AI hydra and prime are notoriously difficult without the right equipment due to the materials used to make LED module boards. There is a good chance of destroying the board if the temperature profile is not followed.
Also, depending on the age of the light, Prime and Hydra use very different LEDs. Those cannot be swapped between lights.
Example of Hydra LED:
Example of Prime LED: