I woke up this morning and a print I had going over night had an issue on my A350. The head someone got backed up and I had a massive blob of filament go up in the head. I was able to clean it out but the blob actually pulled out the thermisister. I replaced the whole hot end but I remembered reading on here about using Arctic silver for the probe. So I thought it was a good idea to use it.
I got everything back together, fully calibrated again. Even used the controller to load filament just fine. I noticed there was an update that dropped this month so I applied it. I turned the OctoPi back on after it was done and then loaded a print.
I noticed the nozzle temperature was nuts. Bouncing from 100-290 very rapidly. I watched through the camera and it was going through the motions of printing but there was absolutely no filament coming out. I stopped the print. and it is still bouncing around after being stopped for 15 minutes.
Is my hotend toast? Or is it the module? Or the update?
Okay… So I just noticed that my temp shot up to 523C! Went downstairs to check if it was on fire and it was stone cold.
I powered everything off. Unplugged OctoPi. Rebooted and then noticed the controler said the nozzle was 329C (still cold BTW). I went into the control part and it wanted to do homing… and it got stuck there and wasn’t moving anything.
I powered off and waiting a few minutes and turned it on. Went back into the control section and the homing worked. Then I went into the nozzle to see if I could load more filament. The temp was bouncing all over again. 69, 140, 220, 83, 198, 250, etc.
I’m I crazy to think this is the firmware? I did the nozzle and filament load before the firmware upgrade and it did a steady increase without an issue.!
I would guess a shorted out thermistor that’s intermittent.
Check your connectors and wires leading to the plug and make sure that nothing has come loose or that there’s a problem with any of the insulation.
If you have an ohmmeter you can check the resistance of the thermistor.
-S
Measure the resistance of the thermistor. It should be a constant resistance at a steady temperature. As the temperature rises the resistance should decrease. It’s the 2 center pins of the hot end connector.
My room was around 65 degrees F and measured around 110k ohm. Just an example I don’t have any specs on it.
Also make sure it is all the way in, they come out pretty easily.
i had it happen before, the pins on the connector were a little malformed and werent making good contact, straightened it out enough to get them plugged well.
Not Electrically Conductive:
Arctic Silver 5 was formulated to conduct heat, not electricity. (While much safer than electrically conductive silver and copper greases, Arctic Silver 5 should be kept away from electrical traces, pins, and leads. While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths.)
And more importantly:
Extended Temperature Limits:
Peak: –50°C to >180°C
Long-Term: –50°C to 130°C
Your hotend is constantly above 200 degrees C
Boron nitride pastes are better suited for this application.
Boron nitride paste is an easy to get solution and works quite well. slice engineering sells a lil syringe of it for like 5-10 bucks or something like that. i will always make sure i have it on hand.
if i wasnt a lazy fucking slob and actually read your entire post i would have seen the arctic silver sooner.
