cant use i2con Pro Mini but work fine on UNO r3

hello
i am new to arduino and written a small project that part of it show LCD characters
i developed and tested with uno r3 and every thing work just fine and LCD show desired texts

but when in switch programmer and borad model ( witout any change in my code ) to Aurduino pro mini
( 5V with 328P ) (chipset is 32 p MU - borad is BeeStore Version )
every things works fine but LCD that is SHOW a full top Line all pixels ON

ive tested without I2C connection and it seems when there is no i2c data it will show this top full on line

so my problem is some how pro mini could not enable i2c or don't send
signal to lCD i2c controller (PCF 8574T)

ive searched and read some topics that suggested add pullup resistors
ive tried two 4k7 from vcc to SDA/SCL but result is the same

is there any special guide for Arduino pro mini ?
is there any way that i check signals on SDA/SCL witout having a osiloScope ?

thanks

Have you tried the I2C scanner test sketch? Does the device show up at the correct address?
http://playground.arduino.cc/Main/I2cScanner

mohandes-mehran:
hello
i am new to arduino and written a small project that part of it show LCD characters
i developed and tested with uno r3 and every thing work just fine and LCD show desired texts

but when in switch programmer and borad model ( witout any change in my code ) to Aurduino pro mini
( 5V with 328P ) (chipset is 32 p MU - borad is BeeStore Version )
every things works fine but LCD that is SHOW a full top Line all pixels ON

ive tested without I2C connection and it seems when there is no i2c data it will show this top full on line

so my problem is some how pro mini could not enable i2c or don't send
signal to lCD i2c controller (PCF 8574T)

ive searched and read some topics that suggested add pullup resistors
ive tried two 4k7 from vcc to SDA/SCL but result is the same

is there any special guide for Arduino pro mini ?
is there any way that i check signals on SDA/SCL witout having a osiloScope ?

thanks

Verify your circuit wiring.

As you have identified, the LCD is not being initialized. The easiest explanation, is that you have miss-wired it. Verify you are using A4 as SDA, and A5 as SCL.

Chuck.

thanks
yes wiring is correct
after i fried my arduino for a unknown short ive tested code with Nano and result is normal as it is on UNO r3

so i did not find out what caused this problem but i m sure it was not wiring also address is correct as it worked on other broads normally
thanks