Zumo LCD does not show any signs of power

I have bought and assembled a Zumo 32u4. The robot is assembled besides the sensor bar. I have tested many example programs such as MotorTest, and the Balancing program which have worked. The only problem came when I tried to use the lcd. I used the Lcd test code, but it did not work. It will show no signs of turning on normally, though I accidentally plugged the lcd in wrong once and the top row dimly lit. I am reluctant to buy a new lcd since it did show signs that it does work.


Unfortunately, plugging the LCD in backwards is very likely to damage the LCD, and the behavior you are describing is consistent with a damaged LCD. Have you tried adjusting the contrast potentiometer to the left of the LCD connector on the Zumo 32U4 board to see if that fixes the problem?

If you need a new LCD, please email us with your order information and we might be able to help you out with a discount on a replacement.


Thank you for your quick reply. I tried wiring the LCD Ground and VCC to a corresponding Ground and 5V pin (on the right expansion of the Zumo), then I wired the Contrast Pin to ground. The top row was completely Lit, all boxes (not sure what to call them) with the darkest contrast. I then tried wiring the contrast pin to the normal corresponding LCD pin, but nothing happened. I am wondering, what is the default contrast of the LCD? Sorry for the late response.

The LCD does not have a default setting. The potentiometer should be adjusted for your preferred viewing. If adjusting the contrast potentiometer as I suggested does not fix the problem, it is likely damaged.


It turns out the contrast was the problem. I didn’t know that the contrast could start at any point. Thanks for your help! :slight_smile: