OLED Display 16x2... doesn't work

[mancio61]

Today I try to wire and use the new OLED Display 16x2 that arrived yesterday.
Following the suggestions catched on this forum, I use the standard Winstar_OLEDDisplay.py and the RaspDacDisplay.py files.
I changed the few constants (e.g. Debug, Log, TimeZone etc.) in the code.

The wiring is this:
1    GND                 -> 6 GND
2    VCC                  -> 2 (5.0V)
3    not wired
4    RS                    -> 26 GPIO7
5    R|W                  -> 14 GND
6    E                      -> 24 GPIO8
7,8,9,10 not wired
11  DB4                   -> 22 GPIO25
12  DB5                   -> 18 GPIO24
13  DB6                   -> 16 GPIO23
14  DB7                   -> 15 GPIO22
15-16 not wired

The problem is that the display doesn't light up. 
I try to run alone the WinstarOLED_Display.py driver and it works, printing on the console "OLED Display Test Started" and after some seconds "OLED Display Test Ended"...
Running instead the RaspDacDisplay.py file, it runs with no errors, but anyway no light from the display....

What can I do? It could be a display problem? Even the DBx wiring could be wrong, anyway connecting it to 5V and GND... at least it should be light up....
Any ideas?

thanks!
Andrea