Printer stops working after a few seconds

[Ollie2015]

When I boot up my prusa i3 pro b it works fine for about 3-5 seconds but after that the lcd gets unresponsive, show lines of black blocks and the sanguinololu stops following commands. What shall I do!? help me!

[Sherry]

please swap the wires connect to LCD,if it doesn't work,you try to reburn the firmware.

[Ollie2015]

I don't think the wires are the problem because the printer works fine for a moment, exept it can't communicate with the computer. Then the blocks start to appear. I am trying to re-upload the firmware but I am not shore that it is the problem. Thank you for your help

[Sherry]

When I boot up my prusa i3 pro b it works fine for about 3-5 seconds but after that the lcd gets unresponsive, show lines of black blocks and the sanguinololu stops following commands. What shall I do!? help me!

hi,please tighten or loosen the small screw at the back of the LCD.it's used to adjust the contrast ratio.