Posted by: @paul42

That problem is gone, but the nozzle now has filament stuck inside it, with no good way to remove it.

So, the way I resolved (PLA) nozzle clog on a HF nozzle was (based on support's advice) as follows --

If you have a drill or something else (Nozzle Cleaning Wires) to reach into the nozzle (from the filament side), measure where the clog is.

Then, based on the position of the clog, heat that place up with a hair dryer, and gently poke it with the stick towards the nozzle tip.

The reason hair dryer works is because PLA has super low glass transition temp, so even hair dryer can soften it up quickly.

Once you moved the clog past the heatbreak and well into the heated part of the nozzle, you can stop, and do the rest on a printer with a purge.

---

Again, worked wonders for me. YMMV.

Posted by: @paul42

badly mangled end of the filament causing it to get stuck above the extruder.

That problem is gone, but the nozzle now has filament stuck inside it, with no good way to remove it.

I've been printing since about 2018, when I bought my Prusa 2.  It has been upgraded to a Core 1+, and it is still very reliable.

My Prusa XL is running on another workbench.

This XL is causing me the current issues.  This would be the first time I have had to dry a new spool of filament, but I will give it a try.

I suspect this isn't the problem, since this is the third spool I have tried, and it is the 2nd new one.

If the filament is badly mangled is it due to the ramming procedure? Or is it getting chewed on in the nextruder gear? 

As for new filament being damp, here is an example. Left is a brand new roll of Prusament PC-CF printed immediately after unboxing, right is after drying 8 hrs. The filament bag still had it's vacuum seal intact. It was opened 3 months after the manufacture date.

That problem is gone, but the nozzle now has filament stuck inside it, with no good way to remove it.

I've been printing since about 2018, when I bought my Prusa 2.  It has been upgraded to a Core 1+, and it is still very reliable.

My Prusa XL is running on another workbench.

This XL is causing me the current issues.  This would be the first time I have had to dry a new spool of filament, but I will give it a try.

I suspect this isn't the problem, since this is the third spool I have tried, and it is the 2nd new one.

Checking for instructions on how to disassemble this.

I have a few different types of filament dehydrators.

Posted by: @paul42

New spool of PETG.  New .4 brass nozzle.  Stopped extruding after a couple hours of printing.

Got the typical clogged nozzle clicking sound.

Back to trouble shooting.

grasping at straws, I will try a 3rd cold pull.

Still the most likely explanation is a heat creep clog. One thing to try is to pick up a tube of thermal paste. I use this (sparingly) on all my nozzles. 

Beside clogging other possibilities are:

• debris in the nextruder gear
• the filament is no longer lining up with the nozzle heat break tube due to a problem with Nextruder main plate. 
• Nextruder planetary gears out of alignment. Try run the gearbox calibration. 

Got the typical clogged nozzle clicking sound.

Back to trouble shooting.

grasping at straws, I will try a 3rd cold pull.

Posted by: @paul42

printing well for months.  

I've swapped out the nozzle and the filament.  

Prints have been a mixture of PLA and PETG.

Run the fan tests and perhaps remove the heatsink fan and use some canned air to blow out any debris. I this point I would (if it were me) disassemble the Nextruder and look for debris or broken parts, strip the grease from the planetary gears and relube. If not comfortable with that then contact support over chat. They can walk you through dianosing the issue.