Do you have any extensions? If you do then they will not work with the faceplate disconnected.
And the cabling to the extension is very likely the cause of the crackle. Absolutely typical symptom of a break in the cable somewhere. If the extensions are not in use what you can do is pull the wires off the back of the faceplate and then put it back in place, just to make things neat.
Otherwise you will need to locate the broken bit of cable and replace it if you do need the extensions working.