I am also having this issue with my P2S. I have 2 HTs that feed into a 4:1 splitter, which then feeds into the buffer. I keep getting errors that it won’t feed through the extruder and requires me to pull back the filament and look for where the filament is flat-spotted. I snip at that point, restart, and then it works. I have noticed some other filaments used in the HT; the filament is all chewed up. I tried to keep the path short and smooth, but the problem persists. It just chews filament. All firmware has been updated.
Here’s what solved my problem:
In my P1S, I was putting 4-1 splitter AFTER the buffer and extruder fail notification was saying “abnormal activity on the buffer” so put the 4-1 splitter BEFORE the buffer, connected AMS and HT to splitter and it worked.
This exact same thing is happening to me with the H2C and 2 AMS HT hooked up to 4 to 1 adapter, then into the left extruder. The filament nearly makes it to the extruder but then gives up and unwinds and tries again a few times.
well i have 2 X1c with ams2 pros and each with an ams-ht. they have been rock solid. they run pa6-cf only without any issues. But I just got the p2s and well that is a whole different story. 90% of the time it will fail to load the filament. Ihave changed all the PTFE lines with no change. i have inspected the filament for crush with no signs of damage. I watch the filament go from the HT all the way to the head and it always stops short by 25mm . the P2S doesn’t support manual loading of PA6CF also. so when it fails to load it leave the 5ft of PA6CF in the line. with no way to pull it back but manually yanking it out to the machine or dis connecting all the PTFE tubes to cut it off in sections. or load from the AMS another filament witch always goes perfect then try again. it is almost like it is not calibrated correctly to load PA6CF in the P2S. the loading Pressure for the filament/ or length to the hot end is not right. It takes about 5 times trying to get the filament to load before it does finally load. at a cost of 1.5hours of time and 32 ft of PA6CF. the real kicker is this will happen even after it just finishes printing a plate with that same filament role. It will pull the filament back at the end of the print and not be able to re load again. so frustrating.
Well, I have a very similar problem with P2S and AMS HT.
Both new, bought this month.
But I think that the solution is trivial on one side and complex on the other. Complex because Bambu Lab should make a revision of the printer firmware.
Why?
Well, my AMS HT sits on the side of the printer, that is why I noticed that filament reaches to just a few centimeters until the extruder, repeats this a few times and report an error.
But, since the lid of my printer is free, I opened it, and moved just a little that internal PTFE tube. Solution found!
There is just to steep bend, to narrow arc of the PFTE, when extruder is in home position.
Bambu Lab should correct firmware so, when filament loading is in progress, the extrudor head should move to front right position, so the PFTE should be as straight as possible.
I do not know how to let them know that, so if someone does, please.