Blade 120sr loose wire

[Enquisiter]

I have a blade 120sr heli but when battery inserted led light flashes red but no response. I noticed what looks like a loose wire (see pic attached) anyone any idea where it goes please?

 

[Mr NCT]

I don't have one but here is what rcgroups says

https://www.rcgroups.com/forums/showthread.php?1958897-Blade-5-n-1-Control-Unit-120-SR