Geeetech

Hello,
I assembled my printer Prusa I3 C dual extruder, but I have a big problem : without temp sensor from nozzles connected, temperatures indicated on LCD is not 0C but around 70C (for both extruders).
For heat bed, no problem, it follow the room temperature (around 22C)
I can't print anything !
It's a big issue, I think there is something wrong with the GT2560...
What do you think?

Could you please take some pictures of what LCD screen displays before and after heating .

here the status at start of the printer, without any thermistors plugged :




If i plug the heatbed thermistor, it indicates around 22°C, as the ambiant temperature.
I I plug 1 or 2 thermistors from extruders, incorrect temperatures are not moving.

I can't take picture "after heating" because of the bad T° feedback, the temperture of nozzle reach a very high level and plastic is burning (not melting) with some smoke...

Please give me a feedback.

here is the view of my LCD screen when starting the printer, all thermistors are unplugged :


If I plug the heatbed thermistor, it reaches to around 22°C, room ambiant temperature.
if I plug 1 or 2 extruders, temperatures on screen do not change...

I trieed to start nozzle heating but plastic in nozzle started to burnt instead of melt with lot of smoke.
Extruders temperatures are not changing a lot too.
I think PID heating management is disrupted...

Please could you tell me what to do? New PCB ?

Let's check if it is firmware issue, the firmware has bee sent to your email.

I loaded the firrmware received and it changed nothing, still high temperature at ambiant room temperature.

Do I need to change my board?

Do you feel hot when you touch the extruder or hot bed?

I do not feel hot when I touch any extruders.
Hot bed is working properly.

Before you plug all themistors, the LCD will display "0/0, 0/0, 0/0 " and "min temp error".
After you plug all thermistors, the LCD will display "ambiant temperature/0" without error.

T'es I konw but there is something wrong!!!!!
Before I plug all themistors, the LCD is displaying "68/0, 76/0, 0/0 " and "ultimaker ready".
After I plug all thermistors, the LCD is displaying " 68/0, 76/0, ambiant température/0" and "ultimaker ready"

Please find a solution.