I thought you switch the gimbal and the swap worked.Not undersanding how it would be the gimble if the gimble works properly on one drone and not the other. If its working on one, wouldn't that mean that something else was wrong with the drone it's not working on (bad cable or board)? Guess I'm not following your reasoning.
I do want to thank everyone for taking the time to respond.
Anyway, now you have two set of everything, start with a set that works; just keep switching parts until you find which part is not working. Return or replacing the faulty part.