ST7920 and Arduino MEGA short

Hello everybody. First of all sorry my English mistakes.
I have an Arduino Mega and I bought a LCD 128x64 with a ST7920 chipset. I have connected it in serial mode but everytime I connect it, Arduino just shut down. I've found that if PSB pin is NOT connected Arduino don't shutdown but when I connect it to ground it shorts.

My ST7920 pinout is:

PIN 1 on LCD [VSS] to Ground
PIN 2 on LCD [VDD] to 5V
PIN 3 on LCD [V0] to middle pin of the POT
PIN 4 on LCD [RS] to D12 (arduino)
PIN 5 on LCD [R/W] to D13 (arduino)
PIN 6 on LCD [E] to D11 (arduino)
PIN 15 on LCD [PSB] to Ground
PIN 17 on LCD [RST] to D10 (arduino)
PIN 18 on LCD [VOUT] to Pot
PIN 19 on LCD [BLA] to 5V
PIN 20 on LCD [BLK] to Ground

And the constructor I'm using is: U8GLIB_ST7920_128X64 u8g(11, 13, 12, 10); //E = 11, RW = 13, RS = 12, RST = 10

Thanks for all.