Problem with serial LCD- maybe contrast pot

Hello-

I am working with LCD-00813 http://www.sparkfun.com/commerce/produc … cts_id=813

It is all dark and I cannot even get the Sparkfun logo to come up anymore.

I thought I had turned the contrast potentiometer in the wrong direction too many times- maybe. Or else the LCD is broken.

So which direction is bright and which direction is dark?

What is the resistance of the contrast pot? I measure 12Mohm with power off from VCC to GND and 2.5Mohm with power on.

From GND to wiper, I measure 1.9Mohm with power on, about 8k from VCC to wiper.

What resistances should I be trying to get when something is visible on the screen? Is the pot referenced to VCC or GND?

Mohms seem high.

Thanks!

Nora

Yes it was the contrast pot. I soldered another resistor in parallel with it and now it works.

Nora