Unresolved Filament extrusion issues

Well, my robo R1+ was working good. Then, tonight I had a weird filament issue I cannot explain. First, here's my upgrades:

• Marlin 1.1.0 firmware from WheresWaldo.
• OctoPrint server on a Raspberry PI.
• Simplify3D for the slicer.

I successfully print about a half dozen prints in this configuration including feet for the robot and a rather large Optimus Prime figurine for my son. I turn on the printer today and the setup looks fine, but I ran into a weird issue. Here's the facts:

• Ran a print. I have the start gcode set to prime the extruder before print start. The extruder primes nicely with a quick 3mm priming sequence. Filament moves into the hot end and appears out the nozzle. The print starts. For some reason the filament is not feeding into the hot end. I can see the gear turning.
• I stop the print. I set the temperature through the admin interface and did a manual extrude of 5mm which worked. Filament fed through and came out the nozzle like it was supposed to. Retract works too.
• Ran a different print and it happened again. Did the manual extrude and it worked just fine.
• I cleaned out the hobbled bolt just to be safe. It wasn't too bad.
• So, this time I put a mark on the filament with marker and sure enough it moves with manual extrude commands in the interface but not during a print.

At one point OctoPrint disconnect to do an unhandled temp probe. I suspect the hot end heater or temp probe is malfunctioning causing the filament to be blocked? Every time I did a manual feed I had to set the temp of the hot end manually to 210 and did it shortly after it reaching temp. I don't think it's a hard jam because I can manually extrude with GCode. I also think the OctoPrint server is running ok because the extruder gear is turning. It's all very weird.

Any thoughts?

 

Geof,

They were done over the course of 4 days. I turned off the printer and the OctoPi server at least a few times during that stretch.

I will try it using MC and see what happens.

 

I will check that. I had adjusted the offset properly. I will raise it up to a high level and check if it extrudes.

 

Also, why I am thinking about it. The current home routine does one touch point in the center of the plate for the Z-Axis. Traditionally I have always homed each side of the gantry individually on my CNC router. What is the adjustment mechanism if the Z-Axis leadscrews get out of alignment?