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Topic: Pololu LCD 16x2 display problem (Read 6036 times) previous topic - next topic


Hi guys!

I'm having some troubles with a parallel connection Pololu 16x2 LCD. When I bought it, it worked fine! The next time I mounted it, it didn't worked; only two black bars appeared on half of the screen.

Some of the things I've already tried are:

  • change the pins (first time I used the pins from LadyAda's guide, here);

  • delay the first write on the LCD (put a delay() on the end of the setup() function);

  • used a power supply instead of the USB to power the Arduino (maybe it could be a power problem...);

  • made a new board for the connections, because the first time I tried the display it was on a breadboard and it could have some bad connection or something like that;

  • used another library (LCD4bitLibrary).

I noticed that on the back of the LCD there is place for 6 resistors (R1 to R6) and the R6 is "missing"; don't know if it should be there or if it shouldn't; it doesn't seem like that any resistor has been soldered there. I couldn't find any picture of the back of the LCD, so I can't confirm this.

Can anybody point me a solution or a tip for some other thing I should try? Can it "broken"? I'm using Arduino 0022 IDE.

I also uploaded 2 photos for the described problem: one with the black lines and other of the back of the LCD with the resistors (sorry for the bad quality of them…).

Black lines:
Resistors (R6 is the top resistor on the right side):



I wish to help but can't see the picture from the broken links. Try reposting the pictures, disconnect all the wires and only leave gnd and 5V. If black boxes don't show and instead stripes show, the LCD is damaged, possibly near the conducting rubber. Maybe servicable.
Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter


Hi liudr!

Sorry for the links. Here it is for my flickr set: http://www.flickr.com/photos/jmpcm/sets/72157625945346394/

I've already tried to connect only VDD and GND (pin 2 and 1, respectively) and appears the bars I referred. What do you think?

Thanks a lot!


Such a clear-cut block-no-block image! I think maybe one of the controllers in the back (the two black epoxy bumps) is dead or its connection to the lcd panel is bad. The rubber between the circuit board and the lcd glass panel might be dislocated. How do they look?

Refer to figure 1 here:

Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter

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