This is discouraging. I hobbed a new bolt, set everything back up,

This is discouraging. I hobbed a new bolt, set everything back up, got things up to temp, and the thermistor popped out of the hot-end.

Got it relocated, and now the heater isn’t heating. the RUMBA is showing 9.3 Volts going to it, and it’s hanging out at 50 C.

I have heard you can burn up components that way. Thermistor shows a lower temp than it actually is and so it throws too much heat at the component and burns it out.

I melted an entire J head when the thermistor and/or input went south ! Fortunately I was about to install an E3D (all metal).

@William_Frick be careful, that E3D can get hot enough to melt aluminum. That’s why I fire cement my thermistors in place. Now, if a thermistor goes…that’s going to be hell.

Woah I had no idea that it can get that hot! Can you confirm by hand if it indeed isn’t heating? What is the resistance of the heater? It should be low (less than 100 ohms for sure id think)

After that it dropped to ambient. It doesn’t heat anymore. I was under the impression the resistance would be huge, it is converting all the power to heat.

I used high temp copper gasket maker to retain the thermistor. By the time I get a new heater, I’ll have kapton tape I can use.

@Mike_Miller The lower resistance > the more current drawn > the more power (heat dissipated).

@ThantiK Probably could but not nearly as quickly. The active cooling would slow it somewhat. Besides that episode cost me 3 +weeks of printing and I am determined not to let that happen again !

@Mike_Miller My thermistor is secured with Kapton and then the entire heater block has 1 layer of self vulcanizing tape around it.

Is it likely I’d find self vulcanizing tape locally? (I’m amazed at the little fiddly odd things these printers take that can’t be sourced locally easily. )

The leads for the heater are showing an open circuit, I’ll tear into it tomorrow.

@Mike_Miller Mine is from UZ Engineered Products. and is called ‘Wrap n Roll’ . They are in Cleaveland OH. It is rated to 260 C and so far is holding well. Try getting a EPCOS thermistor in Canada ! Almost everything is an online store somewhere else .

@Mike_Miller , you can also buy the silicone tape (I’ve called out fusion tape for ages) off of McMaster Carr. And I believe even Amazon

Pulled the extruder assembly apart…one of the wires wasn’t well soldered…so, that’s cool, I can fix that for free…but the collar for the ‘J-head Groove Mount adapter’ delaminated. <grrr.> I’ve got an email into the guy I bought the printed parts from…I’m also considering looking up anyone in South Denver that could print an STL for me…

edit: yeah, the parts upside-down…it was dark in the office. :smiley: