The antenna cable is coax and needs to be shielded or it would just be worse at it's job, likewise if it were shorted along that run it would be doing no real good.
The LC filter is on the power board also, Z1, Z2 and Z3, so make sure all of that is still intact, or try another power board if you have another of that same version.
There's 11 tiny components on the SOC board of the MCU board for the antenna filtering also, any of those missing could frak things up.
Maybe see if the controller can be updated in the dashboard.
If it connected wireless to another device, be interesting to see how it acts around another XB1, though if that also failed then you're probably looking at some security thing failing. I'm sure there's all manner of that kind of crapola in there, and unless updating the controller corrected that you'd have to swap the MCU off a good board to 'fix' it.
