No display on screen!!


New member

I have followed the guide at
except for instead of molex connector used a usb source (also 5v).

Although when i plug the usb into a 5v source nothing happens at all. I have checked all the connections with my multi-meter and they are all connecting and i have checked for shorts and found nothing...

Any help would be appreciated.
Thanks Guys
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If you are trying to get power from a USB socket, it may not work. I believe that USB sockets must detect a certain resistance combination on the signal pins before the power is switched on to the device.

Note that the last picture in the article you linked, showing the display with a row of blocks, does not mean that it is working. It only means that the power has been connected correctly. The display will not "work" until the initialization commands have been sent.

[SIZE=-1]Earth (Black wire on Molex connector)[/SIZE] - [SIZE=-1]This adjusts the contrast of the LCD digits. Earthing
pin 3 provides maximum contrast. A 10k pot can be used to provide a variable value if required.[/SIZE]
[SIZE=-1]This is not true. The best contrast is about 0.5 volts above ground, so a pot should be used.



New member
Would a molex connetor from a serperate power supply work? and also how would i with the 10k pot would i just solder it in between ground and the lcd?