I am hoping somebody will be able to help me with an issue that I am currently having with my 20x4 LCD display. I used this display perfectly about 3 years ago and all worked fine, I dug it out the other day as I have a new use for it and it hasn't been stored in the best of conditions. Anyways I wire it up to the Arduino and upload some basic Hello World code and the thing springs in to life and tries to display the text.
I say tries because the display is lit up, the contract set correctly and some of the text appears on screen but no all of it as you can see in the below image.
At first I thought it could be an issue with my code, however I looked back at my old files from years back and found the original code and wiring I use to use with the display when it use to work fine. I then changed the code to display the text on line 2 and got this result;
And finally I then decided to remove the contrast resistor that I have in place and turn the contrast all the way up as well as removing all text from the display so that I could fuly see and understand the pixels and this was what I got;
So I am completely lost, is the display knackered, can it be fixed? Its as if the pixels have all shifted out of line so does the LCD display have a some kind of on board brain itself that could have corrupted code on, if so can that be reset?
The "zebra strips" does not have good connection. You can try bending the tabs on the metal frame, remove the LCD glass (remember orientation - it does not work when rotated 180 degrees) - clean the zebra strips, PCB and glass with rubbing alcohol and a cotton swab. Reassemble, making sure that everything is pressed tightly together when bending the tabs back. I can recommend reassembling the display while it's on so you can see when it's aligned correctly (if it's shifted a bit to the sides, the connections does not line up properly)
Fantastic, thanks for the reply I will be sure to give this a try as soon as I am able to and will let you guys know the results. Just glad to hear that there is a possible solution!
So I have just tried this fix and sadly it has not solved the problem. All connections were cleans and everything reassembled and yet the exact same pixels are still broke, which kind of confirms its not a connection issue because surly after taking it apart and re building the entire thing then slightly different pixels would be dead or alive if it was connection related.
Anyways thanks for the idea, another thing eliminated, and if any body else has any suggestions then I would be glad to hear them.
Ah that's most likely the case then as it's been stored in a rather damp shed for a while now. Fortunately I can use it still for this project as I only need to display 4 digits which fit on the work portion of the screen! But I will invest in a new one soon!
