Default [Q] Only wcdma on i9505, no gsm signal

Hello xda ,

I have a problem with my i9505 .

I have no gsm signal.

When i choose "GSM only" it says "emergency calls only" , thus in the areas without 3g , my fathers old brick is better than my s4.

If i chose "WCDMA only" it works in the areas with 3g .

If i choose "WCDMA/GSM" if the 3g signal is weak , it search for 2g... doesn't find so i get again "emergency calls only"

If i choose "LTE/ WCDMA / GSM" and i try to call somebody it brings up the calling screen but nothing happens until i get " line busy "

I tried a lot of different modems with no luck , my google skills failed me too ... so here i am .

Any sugestions ?

PS. No waranty here. So " send it to samsung " is not what i'm looking for .

Thanks for reading.