Hi everybody,

I've just throw out the melzi board on my Wanhao I3 for a ramps 1.4,
I also changed the thermistor for a thermocouple type K with the AD597, But I have strange reading.
It heat up great, i can go up to 280° without problem (i'll print around 270 for the taulman 645) but as soon as I turn on a stepper (the extruder is the worst) my reading drop.

If i'm at 200°C,

With the X-Y-Z axis motor : it drop to 160-180
with the extruder, it drop to 50° and to 150 when I ground the shield of the thermocouple wire.

So i need your help, i'm kind of new with the 3d printing world...

Thanks!