Very dim-no backlight on KS0108 based LCD

I have a Sure Electronics 12864 graphic LCD, model # KCM12864-C, based on the KS0108 driver chip. I am using openGLCD library. I can compile, load and see graphics from example sketches, no problem.

However, there seems to be almost no backlight and the contrast adjustment is very critical and the screen is really too dim to be usable - I can only barely see the images. I have triple checked my wiring and all is as it should be.

On scanning the datasheet for this screen I have noticed that the specs state that the VDD-VO (operating voltage for LCD) should be typical 8.5VDC !! Not 5VDC, so I wonder if this is why the screen is so dim? Do I really need to put a 9V battery on this thing? Either that or my device is faulty?

Does anyone have any suggestions or has noticed this with a similar device?

Thanks for any assistance...

Can you show how you have wired up the panel?
And provide a link to the datasheet for you exact glcd.

Contrast and brightness (of the backlight) are two different things.
Are the pixels faded (contrast issue) or is the backlight dim (backlight issue).

Are you using a current limiting resistor on the backlight?
What resistor you need to use (if any) depends on the glcd.
Some need them and some don't.
If you have one that needs one and you don't use one, it can quickly burn out the backlight which makes it very dim or even totally off.

If you have a backlight that needs a resistor, if you use one that is too large, the backlight will be dim.

--- bill