I bought a used Castle Mamba Monster X Esc. When I plug it in all I get is two short beeps and one long beep. I see this is an RX/TX issue.

So I tried swapping in a different RX....same deal.

I then tried another RX, one that is currently mounted in my savage truck. Same deal. Now the RX in the savage (that I was using to test) doesn't work with the motor/TX that I was using before testing.

Any ideas what is going on here? Is this ESC just frying all my RXs?!

The wires from ESC --> RX were hot to the touch.

Thank you!