Welcome to the SeeMeCNC Community

So when calibrating I did not realize holding down the keys on the keyboard would send my hot end down way to far!? I tilted it askew, regrouped and finished cal more conservative. When going to test print I got an error HEATER DECOUPLED, on further investigation I ohmed out the hot end thermistor and found continuity from the soldering points to the hot end heat sinc. I had ordered new ones a week ago for a first aid kit, only thing is they are screw in type, planning on tapping the correct size And replacing tonight. Any tips, and am I on the right track?

There's no need for a screw-in thermistor on the HE280. Just replace the thermistor if it's damaged, and go.

g.

Actually, I'm suspicious of your diagnosis. One side of the thermistor is attached to ground. That ground is also connected to the circle pad that the heat sink is mounted on. So continuity between the heat sink and the ground side of the thermistor is normal and expected!

As for the other side of the thermistor, make sure you disconnect the 8-pin connector to remove the rambo from the circuit before measuring. THEN measure between the two thermistor leads. If you get a reading close to 100KΩ at room temperature, the thermistor is probably fine, and the leads are not shorted together at the hot end.

So, assuming that checks out, were're back to the quesiton of what does the "HEATER DECOUPLED" error actually indicate?

From what Google tells me, the HEATER DECOUPLED error happens when power is applied to the heater for a certain amount of time, but the temperature either doesn't change, or falls.

g.

I installed the thread in thermistor in the m3 hole and brought the temp up, used a fluke meter to check an it was 3c off witch is ok for me. When I replaced it is solders in a quick connect so next time it will be plug and play . Off to the races! FYI when she went bad matter control had a pop up saying hardware failure.