After my previous problem, I bought a new I2C and LCD (1602). At first, I've tested I2C through I2C address scanner (Arduino UNO R3). No I2C found. I used MEGA and found at 0X27. I think: 1)Pull up! 2)damaged A4 and A5! for pull up, I connected a 5k Ohm resistance (from rear and middle pin of potentiometer) between SDA and VDD and another between SCL and VDD, no thing was detected! for test of A4 and A5, I had no idea but measuring resistance between these two pins (11k Ohm).
Please suggest any solution.