This question was asked on the RC Universe Forum in 2019. The exchange was as below.

Colin

Q: Trying to restart in the hobby and playing with my radios on the bench. I have 3 receivers (AR7000, AR5200, and AR400) that do not power up even when the battery is connected directly. They did work initially so I am thinking I may have inadvertently plugged the battery in with the plug inverted, though I'm not sure what damage that might have done. I do get a real quick "blip" of the led upon first powering up, but then it goes out. I have plugged to the battery and switch harness into another non-spektrum receiver and it works normally. I have a real bad feeling I now have 3 fried receivers, but thought I would put it out here first. Can inverting the battery connection to the receiver do damage to the receiver?

A: You cannot hurt the rx's doing what you mention. The center lead is the hot lead so even if you plug them in backward, you're just reversing the signal and ground leads. Usually a quick flash and then nothing indicates that the power input plug is upside down.

Q:The more I thought about it, that is what I thought, but I guess I just needed to be sure. One receiver seems to be working again, but the other doesn't seem to power up regardless of which way the plug is inserted.