Chart views, the Nav tab, and the Chart tab will not show unless the unit has locked onto the satellites.
If you are outside where the unit’s internal GPS antenna can see the sky, if the unit is in Normal operating mode, and you have waited a few minutes for the antenna to connect to the satellites - and the unit still does populate Chart views or the Nav tab and Chart tab = it is possible the internal GPS antenna has failed.
1st try Restore Defaults ...
If that does help there are 2 options ...
1. Connect an external GPS antenna. Read here about connecting an external GPS antenna to a HELIX 7
https://www.humminbird.com/support/faqs/HELIX_EXT_GPS 2. Contact your HB dealer ...
Rickie