Nozzle Temp Cuts out

[steve220]

Started a print last night. This morning, I see that the printer quit extruding near the end of the print. The timelapse shows the print head moving normally, but no filament is extruding at the end. Plenty of filament available, so that's not it. Heat up the nozzle and extrude filament - everything fine. So I start another print. Bed and nozzle heat normally. Print starts normally. Unfortunately, as soon as the printer starts printing, the nozzle temp starts going down and doesn't stop. After a few seconds, no more filament comes out (nozzle too cold). This now happens every time I print, even with different profiles. Gcode looks good with no temperature commands other than the initial setting of 205 degrees.

Any thoughts are appreciated.

[willnewton]

possible a loose wire or bad thermistor or wonky heating element.

but maybe it is in your software....do you have a separate temp for layer one vs. other layers? You setting might be off.

In s3d you can observe the machine feedback window to see if the printer trying to keep the heater powered. Is the onscreen heating indicator still lit when your print is running and the head goes cold?

Can you narrow the diagnosis down to a hardware or software issue?

[steve220]

Replaced heater and thermistor, but same behavior. I'm running Octoprint/Octopi so I switched to S3D controlled through USB. Same behavior.
I haven't changed the S3d profile I'm using, but tried another one anyway. Same behavior.
To answer willienewton's question, yes, S3D shows that the nozzle heater is still on (red light is on) when the temp starts to drop.

Feels like an iffy wire somewhere that loses connection when the print head starts moving, but open to other thoughts. For grins, I've attached the last gcode I tried to print.

[Bratag]

Because it happens even after the changing of the heater and thermistor I would be looking at the connector between the thermistor/heater and the controller. Perhaps that micro connector has issues. If thats not the case then its tracing the wire back to the board. It seems to be related to movement (if I am reading your post correctly) so Id be looking part of the cabling that is actively moving during prints.

[steve220]

Thanks, I'm pretty sure there is an iffy heater wire. I tested continuity between the RAMBO (Heater +) and the H0 connector at the print head. I can get it to break continuity by jiggling the harness near the top zip tie holding the harness to the frame. I've contacted MakerGear for next steps.

[steve220]

Posting the resolution for anyone who experiences something similar. Turns out one of the heater wires in the extruder harness went bad (broke internally). MakerGear support asked me to open the harness to see if anything was readily apparent, but the wires all appeared fine. I put a meter on the wires to measure continuity between the RAMBO connection and the heater connection on the print head and was able to find the bad spot by bending the wires at various points. With MakerGear's approval, I stripped the insulation at the suspected break point and the break was clearly evident. A little solder and heat shrink tubing put everything right and the printer is working great. A new harness is on its way from MakerGear.

The wire broke right at the spot where the topmost zip tie secures the harness to the frame. I guess the constant flexing at that point caused an iffy wire to give out. Hopefully I don't have further problems with other wires at that same spot.

Big kudos to MakerGear support for their assistance, prompt responses and excellent customer service.