Can't get 162 LCD to work | How can I know if it's broken?

I am trying to get a generic 162 LCD working. The exact model is LMB162ABC. I'm getting a backlight and that's all, nothing else

I have checked and rechecked the wiring, over and over, visually, with a multimeter. Then I hooked things to a raspberry pi and manually set each digital pin to low and high and checked the values at the solder point at the LCD to confirm if the connections are working fine and they are.

I have tried toying with the potentiometer but to no avail.

Could it just be a busted LCD at this point? How can I tell?

Can't get it to work? No wonder - you have the potentiometer connected to 5 V where it should only ever be connected to ground. :sunglasses:

Is it a 10k potentiometer? Connect both ends to ground and the wiper to "Vo" - pin 3, then adjust it until you get a display - either "blocks" on the first line if it is not responding to your program, or whatever your program is sending.

You are absolutely correct. Someone else pointed out the same to me on reddit and it's working now.

Did they include the specific detail that - contrary to many or most of of the tutorials available, the potentiometer should not at all be connected to 5 V? :face_with_raised_eyebrow:

No they did not.
Most tutorials I looked at connected to ends of the potentiometer to 5v and ground and the middle pin to the lcd.

I have a bachelor's in computer science and a very basic understanding of electronics, I can tell that of course I don't need to connect both the ground and the 5v to the potentiometer. I thought that the level of the 5v line would determine how high or low the contrast should be, so I only put the 5v line.

As it turns out what matters is how much current I allow to flow between the lcd and the ground. I realize now that I can just ground the pin since that contrast works fine for me and forget about it