Pixel blocks showing up on a 16x2 LCD with Arduino Mega 2560

Hello people, I hope y'all are fine

To put it simple, I'm pretty fresh at the Arduino world, and was trying my way around with my Arduino Mega 2560 in this tutorial: http://arduino.cc/en/Tutorial/LiquidCrystal, and it came out just fine. I then implemented it on my project: A temperature-measuring circuit with a LM35DZ sensor, and it came out fine as well. I called it a day and powered off the circuit. When I powered up the circuit again, the 16x2 LCD just went wacky, showing up messed up characters, pixel blocks, or even nothing at all. I've tried everything: changing Arduino (a Duemilanove and an Uno), changing the board, jumpers and the LCD, and nothing helped. I even rolled back to the tutorial code, but it hasn't changed.

I'll appreciate any help.

Some like that?

If you see the black bars then it means that the LCD chip Hitachi (or compatible) wasn't initialized.

Yes, exactly like that, thanks

I can't seem to initialize the LCD, and I can't find anything on Google. Any help?

I can't seem to initialize the LCD, and I can't find anything on Google. Any help?

You don't say what country you are in but if you put the term "LCD Initialization" into the US version of Google you get lots of results.

Don

Looks like you might have to tune the contrast pot on the back ....

Looks like you might have to tune the contrast pot on the back ....

That will make the boxes and/or the other stuff that he is already seeing either brighter or darker but it won't solve his problem.

Don