My ipad cant see WIFI signals

hi

I have a problem that has me stumped. Maybe some clever guys can help me out.

I got an ipad 2 WIFI model to repair which had a slight crack on the digitizer and reported as not connecting to WIFI.

When I was replacing the screen I also replaced the WIFI antenna from the mainboard to the surround with a brand new part.

However, when trying to connect to WIFI , The ipad is not picking up any WIFI routers in range , the strange thing , when I enable WIFI hotspot on my Galaxy s4 or my wifes iphone , the ipad sees it ,connects and works perfectly.

I have tried a restore, update to 7.0.4 , new antenna,

changing security , channels and WIFI versions from N to G and still no joy.

I would be extremely grateful if anyone could offer some assistance on the matters

Thanks

Stephen

Dublin , Ireland