Seemingly Broken LCD

I just bought this LCD,

and it seems to be broken. The backlight comes on, but then as soon as it recieves input it shut off. I can't seem to get it working no matter what I try. I have even tried their test code but it doesn't work. I am new to this and would be grateful to anyone who could point me in the right direction. If someone could come up with a compatable test code that would be appreciated as well.

Read this one (not all points are relevant to you),102266.0.html

Saving some money at purchase is probably the source of the problem. I don't have this exact LCD so hope others can step in with inputs.

Their test code is written for a 16x2 display and you have a 20x4 display. You should change this line:

LiquidCrystal_I2C lcd(0x27,16,2); //set the LCD address to 0x27 for a 16 chars and 2 line display

This discrepancy does not make any difference with the regular LiquidCrystal library so it may not have any effect with LiquidCrystal_I2C either, but it's worth a try.


Your display uses a 'Yw Robot LCM1602' serial backpack, which is a ripoff of the DF Robot serial backpack, which may very well be a ripoff of another device. If you do a search for "ywrobot serial lcd" some solutions will be returned.


Now S-5 has been updated to emphasize the fact you have to stick with seller's library. In your case, the seller is not providing a library, meaning, you stay the hell away from them next time. If I wanted another I2C backpack I probably buy from forum member fm's store.