Just completed first build. Need help.

[Ashontez]

Ok, so I just finished putting together the v3 and when I turn it on. The Bed says ~24c but the hot end automatically goes to ~150c and stays there no matter what I do. I'll say "turn off all heat" and it still stays on. I can turn on the heated bed and it works just fine but It eventually will then display "def" on both the hot end and the heated bed, but the hot end does not cool down.

I've checked both the thermistors and they're soldered correctly (I think) although they aren't professional quality by any means.

Help?

[IMBoring25]

If you are running the stock hot end and haven't messed with the thermistor settings in the firmware it sounds like a wiring problem. If you unplug the temperature plugs from the board and check the resistance at the leads you should get something near the 80-100 kohm range depending on your room temperature.

[Ashontez]

If you are running the stock hot end and haven't messed with the thermistor settings in the firmware it sounds like a wiring problem. If you unplug the temperature plugs from the board and check the resistance at the leads you should get something near the 80-100 kohm range depending on your room temperature.

I haven't touched anything in the firmware, i'm not familiar enough with that to feel comfortable changing anything.

How would I check the resistance exactly?

[Mac The Knife]

With a digital multimeter.

[Ashontez]

With a digital multimeter.

Yeah, I figured that much.

What leads should I be measuring exactly? I have almost no knowledge of how wiring works.

Did I wire everything correctly on the bed at least? It still shows up as "def" when I turn it on and I dont know why. Everything should be working but its not.

[geneb]

You're probably shorting the thermistor leads together on the metal plated hole in the center of the Onyx. The thermistor isn't installed properly. It should have ptfe tubing going from the thermistor "bead" all the way back to where it's soldered. For very clear pics of how it should look, grab the 4th Ed. of the Rostock MAX v2 build manual off SeeMeCNC's website.

g.