I think there is some confusion here. The main Vdd (V+) pin should be
at 5V almost exactly (between 4.75 and 5.25). Joe is warning you that
the display may not work properly with Vdd/V+ much below 5V.

Others are telling you about the Vlcd pin. This is to bias the LCD
backplane itself. They are warning you that this pin should not be
left unconnected. It should be tied to ground through a low value
(about 330 to 2K ohms) resistor.

Sean


On Sun, May 2, 2010 at 8:53 PM, ivp <joecolquitt@clear.net.nz> wrote:
>> Problem: When I run it the LCD stays blank (backlight and
>> everything else turns on so its not a power issue)
>
> (I didn't see the original post so the answer may be there)
>
> What is V+ for the LCD ? The display fades below 5V, even
> though the backlight might still be on. I think the lower V+ limit
> is 4.5V to see characters. And LCDs are not forgiving of reverse
> or over-voltage, it is very easy to kill them
>
> BTW, the very first thing I do, straight out of the box, with a new
> LCD is protect it with a piece of acrylic. The panel glass is quite
> fragile
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