Hi,
i bought the k8400 last friday and finished with assembling. Unfortunately the display is shining blue without any information…No “Vertex”, no Firmware…
I tried to update the firmware but the problem still exists. i disconnected the cable and connected it again without any effect. there was no “Reset-Taster” (manuals.velleman.eu/article.php?id=88 (first image)) in the kit but i think that isn’t the problem…
What do I have to do?
Thanks…
There is an adjustment below the LCD to adjust the contrast.
Have you tried that?
http://manuals.velleman.eu/article.php?id=225
Hi,
I have had the same issue.
Did everything I could.
I disassembled the display and left the spacer out.
Now the contacts got together and the display was working.
Then I reassembled the display to the printer with the spacers and it worked perfectly.
I guess, the contacts did not fit perfectly on first try
Best
Frank
Hi,
Thanks for fast response!
I tried both already. I adjust the screw for contrast and assembled without the parts for distance…
First nothing changed but i tried it once more right now and i don’t know why but it works!! 
Yeah!!! Thanks a lot! Now i’m happy and hopefully ready for the first print 
Have a nice day