After two successful prints the nozzle stopped heating up

[Wilron]

Hello All,
I just finished building the RigidBot but after two successful prints the nozzle stopped heating up. I'm not sure how to diagnose the problem. All of the axis controls still work, and the extruder fan is running but the heating element is cool. I have a multi-meter, but I'm a noob with electronics so I don't really know what to check for or how to use it. I'm thinking I should check to see if there is current going to the heating element first, any ideas on how to do this properly?

Thanks

[spiderdaddy]

What is the resistance of the thermistor and the heating element?
Check the thermistor troubleshooting page on the wiki.

[Wilron]

Thermistor is reading 97.5 and the cartridge heater is 0.L, whatever that means. I also measure the voltage coming to the heater and it was 24.4V or so which seems fine. Since I can't get an ohm reading on the heater I'm assuming it is bad. I ordered a few of them from ebay since they are cheaper, and I opened a support ticket just in case.

Cartridge heater is 24V 40W. 6mm in diameter and 20mm in length.
http://www.ebay.com/itm/5PCS-Reprap-24v ... 2ec9f87acc

[greg]

0L is infinite resistance, so it's open. Should be reading ~1.7ohms or so. The heater has exposed wires coming out the back. The insulation is very close, but not embedded in, the epoxy fill. If those wires get twisted while you're routing the cable it's possible for them to touch and short out... but unless you saw evidence of them burning through it sounds like the heater failed inside the cartridge. Good luck with the replacements!

[Wilron]

Thanks for the info, I'll let you know how the replacement goes.

[mavgrab302]

I have posted the exact problem among a few other things..at room temp my thermister ohm'ed at 105 lcd read 26 deg C..find anything that works let me know.. I was thinking more along the line of something on the firmware changing being my lcd had different options all the sudden and thats when heater stopped.

[Wilron]

I had success fixing the issue by replacing the heater cartridge. I had to pick up some JST terminal crimp connectors at digikey but I was able to reuse the white plastic JST housing. My thermistor is fine, so once I swapped out the heater then everything worked fine. I must have shorted out the original when bending the wires to wedge in front of the linear bearing.

[mavgrab302]

Awesome..that is good to know..I guess im buying that bundle of 10 on ebay...