I would check the wiper voltage on the pot. Maybe it is putting out either a very low or very high voltage and biasing the lcd poorly?
On Tuesday, January 30, 2024, Ken St. Cyr <[email protected]> wrote: > Hey folks - > > I'm working on an M100 and having some challenges with the LCD. Here are > the symptoms: > > - No image at all on the LCD > - Contrast dial does nothing > - Beep test passes (boot > enter > beep > enter produces an audible > tone), so it seems the system itself is working > - The LCD works fine in a different M100 > - VDD is reading +5v, and VEE is reading -5V > - Checked the data pins on the LCD with my scope; they all look fine - > looks like both data and addresses are making it to the LCD connector > > > At this point, I'm baffled. Can anyone offer up some advice on what else > to check? > > Thanks! > //Ken S. >
