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Topic: No contrast on LCD screen (Read 1 time) previous topic - next topic

TheWave


Make sure that your power supply hasn't shut down due to excessive backlight current.  Have you considered using a current limiting resistor with the backlight?

Don


I think I did at the beginning but I removed it. Will try again though.

TheWave


Ok one other thing that looks very strange in your photo is the 16 pin header.
I see that the short part of the header pins and plastic is on top of the LCD PCB.
with the longer pins going through the LCD PCB.
This is quite unusual.
Compare the difference in looks between your setup and the pictures
on the adafruit tutorial. (in particular the 3rd photo down)
While the header can be inserted this way and the long pins soldered on the bottom,
normally the the plastic is under the LCD PCB and the short pins are soldered on the top.

Did you follow the tutorial and solder the pins to the PCB or are you just sticking the header through the
holes in the LCD PCB and into the bread board?


--- bill




My header strip was not long enough so I added an extra, I must have placed it in the wrong way. I will change it around and see if it makes a difference. Also no, I have not soldered it. I have never soldered anything and would rather be able to reuse this breadboards. Also will soldering really do anything other than make it permanent?

bperrybap


Also no, I have not soldered it. I have never soldered anything and would rather be able to reuse this breadboards. Also will soldering really do anything other than make it permanent?


No solder = Will Not work!

The header must be soldered.

The tutorial you linked to in the 1st post even warns about this in the second paragraph:

Quote
Next you'll need to solder the header to the LCD.You must do this, it is not OK to just try to 'press fit' the LCD!




--- bill

floresta

#8
Jul 18, 2012, 03:42 pm Last Edit: Jul 18, 2012, 03:44 pm by floresta Reason: 1
Quote
Compare the difference in looks between your setup and the pictures on the adafruit tutorial. (in particular the 3rd photo down)

Bill - Adafruit changed the tutorial recently and I am not sure that I will recommend it any more.  They have switched back to selling a version of display that uses a low power backlight with a current limiting resistor on the pc board so they have removed the recently added information on how to determine the required series resistance from the tutorial.  The photos never did show the resistor. (They do have a disclaimer that the tutorial is only for their products.)  Also, they still have the first bunch of photos with the LCD shown upside down, so the single row of blocks appears to be on the bottom, not the top.

Don

TheWave



Also no, I have not soldered it. I have never soldered anything and would rather be able to reuse this breadboards. Also will soldering really do anything other than make it permanent?


No solder = Will Not work!

The header must be soldered.

The tutorial you linked to in the 1st post even warns about this in the second paragraph:

Quote
Next you'll need to solder the header to the LCD.You must do this, it is not OK to just try to 'press fit' the LCD!




--- bill



What will soldering do that is different than 'Pressing fit' The LCD?

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