Geeetech

Hi Albdiag - it seems to me the manufacturer has made a change to the design, and the JHD204A does not have a contrast function.

Despite days of effort, I could not get contrast to work, however the The LCD will display the data at full brightness.
My JHD204 only showed pink/purple squares until ...

As per my post, all wiring is correct as per the data sheet........KP_OZ

I have bought a JHD204A LCD (20 x 4) display, but cannot get the contrast to work .
I have wired pins 1 and 16 to -ve (ground), and pins 2 and 15 to 5Volts +ve - as specified in the data sheet.
Pin 5 (the Read/Write select) is connected to ground (-ve).
Pin 3 (Vee) is used to adjust the contrast ...