[PINE A64+ 2GB] Ubuntu - Losing Signal

[Arlanps]

Hi @pfeerick .

First of all, thanks for your fast answer.

When I was refering to signal it was monitor Signal, when the signal gone, my Pine64 redLight turned off too.
About the PSU, I have changed to my cellphone PSU charger (5.1V 700MA).
I have burned again my Ubuntu img using Etcher. Here's what I got.

First boot (Keyborad connected at boot), No signal;
Second boot (Keyboard connected after boot), Worked, but after login I lost my monitor Signal;
Third boo (Keyboard connected after boot), worked, yes, worked...
when I opened firefox and tried to open a second tab I just lost my HDMI and the Pine64 led turned off.

Do you recommend what kind of PSU? Any suggestion?

Thanks again