Where is the mistake. can't display anything on the lcd monitor?

Question

Arduino

the screen is on but does not display anything
connected according to this scheme
zelectro.cc/LcdI2Cmodule
I have an arduino uno 1602A

Answer 1

1) turn the contrast resistor, make sure that nothing is really output
2) Using the I2C Scanner sketch, make sure that the display is visible on the I2C bus, and that its address is really 0x27 (maybe 0x3F or something else)

Answer 2

Use the Liquid_Crystal_PCF8574.h library