LCD won't display but does light up


 
R

RobW

New member
OK gang, I have searched the forum threads for a couple of weeks now and can't find an answer to my dilemna. I built a 4.3 and while my screen LCD will light up, it will not display anything. Interestingly enough, my light is on the opposite side of the one in the build videos. Any thoughts as to what I may have missed or where I can check connections?

I can tell the HM is responding, because I can put in the pit probe and the rotodamper will move.
 
Did you adjust the contrast potentiometer to make the display visible? The backlight on the HeaterMeter in the assembly video is on the other side. For some reason, when NewHaven made the LED backlight module (that comes with the kit from the store), they swapped sides. Their cold cathode backlight LCDs still have the backlight on the other side.

If the contrast adjustment just displays a row of squares across the top line, then search the forum for help in troubleshooting bad communication between the two. It is a somewhat common build problem.
 
Ok try checking for continuity from the LCD D0-D3, E, RS to the shift register and SCK, MO, LCK from the atmega up through to the shift register. Also check 5V and GND, and that nothing connects to anything else.
 
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