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I just received my Pi (and parts) and I'm very excited to begin tinkering, though, it seems it hit an early road bump. I am running the latest version of Raspbian Wheezy with an LCD screen from Sparkfun. I am trying to do a simple "Hello World" display.

I began by disabling the OS from writing to the serial console by following these instructions. These steps include editing /etc/inittab and /boot/cmdline.txt to remove ttyAMA0 references. I then constructed the voltage regulator circuit and ran this test python code. Nothing shows up on the screen.

My multimeter confirms that the power being provided is correct. the TXD line (GPIO14) is always held high at 3.3V. When running the test script, my multimeter detects a slight drop in voltage (not accurate since transmission is quicker than the MM). I assume this means that data is being transferred? Is my LCD just bunk? What else can I do to narrow down the issue?

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up vote 4 down vote accepted

I've figured it out. I was contemplating deleting this question, but I decided to answer it instead in the case anyone had similar issues. Turns out the potentiometer for contrast came too low out of the box. The screen always appeared washed out. Adjusting it fixes the issue.

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