Lcd problem on k8400

Hi
I just finished my assembly k8400
the LCD screen only shows a blue screen.
The print head becomes hot and 2 red LED lights up, so I pulled the plug immediately.

I have examined all plug and I found no fault

can anyone help me.

Hi,
Check if the reset button on the LCD is not stuck.

hi
there’s only connection when I press the button

What version of the firmware have you installed?

Hi
I have never had any contact with the printer, only the blue LCD.
so it must be the firmware supplied with it

OK check if the 2 PCBs of the LCD are correctly connected together (it easily happens that the contact pins are not correctly inserted in the terminal). And also that the red stripe of the flat cable is on the left side (when observed from above with the front of the printer facing you).

NB : the reset button is in the small hole above the LCD slit and sometimes can stay pressed by the acrylic panel.

If you remove the LCD assembly, also check if you didn’t partially rip off the rotary encoder when setting the knob in place.

[quote=“raby”]OK check if the 2 PCBs of the LCD are correctly connected together (it easily happens that the contact pins are not correctly inserted in the terminal). And also that the red stripe of the flat cable is on the left side (when observed from above with the front of the printer facing you).

NB : the reset button is in the small hole above the LCD slit and sometimes can stay pressed by the acrylic panel.

If you remove the LCD assembly, also check if you didn’t partially rip off the rotary encoder when setting the knob in place.[/quote]

Thanks for all your responses.

Unfortunately, it all seems to be in order, so I should probably send it to
the manufacturer

You can disconnect the main connector on the printhead to start troubleshooting.

Is it a newly build printer?

Hello,

I have the same problem. My lcd is blue after the first startup.
I have 3 red leds on of x-y-z end.
A green led on the motherboard is on.

What is the procedure to check this mistake ?

Thank you for your help;

mecano3d

[quote=“mecano3d”]I have the same problem. My lcd is blue after the first startup. [/quote]Read this thread, you might find the solution

Check the voltage and Bad contacts between the two PCBs ?

Everything is ok…

I verify all the cables, check the connectors of lcd…

Thanks

Hey I know this is an old topic but I’d thought I’d ring in here, I had the exact same problem with my K8400 as the OP.

I noticed the screen started turning on and displaying text when I started to loosen the screws in on corner. When I tightened the screws, the LCD turned off.

You might want to make sure that the screws on the LCD PCB are tightened evenly so the PCB board doesn’t bend or twist.