Pre-heating the extruder and bed will crash with DEF error

I do not set temp in the code, so I will manual heat the extruder in repeater host and the bed to the desired temp.
When reached, I will start the print.

The last time, often I walk away from the pre heating, as It will take some time. When I expect all has reached the temp, I return.
And now often I see the lcd has the error ' def'. and all heaters are off.

So I reset the board, reconnect the printer and do it again. Than it will work.

What is the def error ?

Thomas

---

www.3daybreaker.blogspot.com

Orca V4.4 rebuild to Ramps with Mk8 and E3D, as well as a Rostock Delta Mini and an OLO in backorder :-)

def = defective.

Ok, that makes sense,
But what could be the defect ?

---

www.3daybreaker.blogspot.com

Orca V4.4 rebuild to Ramps with Mk8 and E3D, as well as a Rostock Delta Mini and an OLO in backorder :-)

Since u say it takes a LOOONGGG time to heat, it may be tripping the temp runaway or whatever because the temp isn't changing fast enough. Once you restart it, it is past a threshold temp and then continues. Check those settings.