Hello guys. i'm lost again
i made several projects using arduino gsm shield with sim900 module (https://www.hetpro-store.com/TUTORIALES/wp-content/uploads/2015/10/3_grande.jpg?x18372)
I used LM256 module to power shield via external jack. For one project (one shiled) everything works great. I ordered 5 more shields, made same circuit with LM5256 module, and modems (all 5 of them) reboots while trying to register to network!
It seems like power related issue. I tried to connect LM module to 12v 2a power supply, to 12v lion battery - result the same, although i have exactly same shield working with same configuration.
Guys, help me, i'm going nuts over this one :(((