LCD lights up but shows no text I've connected an LCD display to an Arduino Uno following the instructions from the Adafruit LCD lesson.



I've used the code sample described in the Adafruit lesson.

What happens after I connect the Uno to the USB cable is that the LCD lights up, but no text is displayed.

I've checked all connections and they look good. I am not 100%sure I have connected the potentiometer correctly, as this is the symptom I usually found online.

Could this also be a bad solder job? It's my first attempt and I guess it did not go that great.



Here are some more images, maybe someone with more experience can spot the error.








Update: here's what the board looks like once connected



and after removing the ethernet shield I get some weird flashes from time to time, only when I switch the potentiometer to maximum on one side, see video at https://i.imgur.com/ZclD2xz.mp4 .

Update 2: I realised that this is a 20-pin LCD screen and re-reading the datasheet and some online tutorials I switched digital wire connections to pins to the LCD 7-10 (DB0-DB3) - same result and then 11-14 (DB4-DB7) - garbled output, shown below. Still no idea what is wrong.
From provided picture it is visible that your display is not alphanumeric display (with most popular HD44780 driver). It is a graphical display (most popular: KS0107 or KS0108 or ST7920). You can count horizontal pixels and vertical ones in the picture to confirm its resolution.
Without too many problems you can drive it with your Arduino. Try to use some of 128x64 Arduino libraries. Also, check the rear of the display for any part number to confirm the driver (search in google).
 Good luck!