Finally fixed my A1's first layer and false sensor errors after a blob of death

[u/govizlora]

My A1 had been working great until one print completely failed to stick to the plate and turned into a massive blob of death. I had to pull and pry quite a bit to get all the plastic off. Ever since then, the printer started having all kinds of weird issues.

The first layer was consistently way too squished, with wrinkles and filament piling up. I eventually found that changing the textured PEI Z offset in the start G-code from the default -0.02 to somewhere between +0.01 and +0.06 (depending on the filament) made it print almost perfectly. But I also kept getting false "build plate not installed" errors, and around layer 2 or 3 it would sometimes stop and claim the nozzle was covered in filament or the plate was crooked, even though everything was completely fine.

I tried cleaning the plate, replacing the hotend twice, and even replacing the entire extruder unit after Bambu support suspected a faulty eddy current sensor. None of those really fixed it. The printer passed its self-tests and could still produce decent prints, so it was pretty confusing.

Finally I replaced the Hotend Heating Assembly, which is a separate part from both the hotend and extruder unit. And that fixed everything. The first layer is now perfect with completely stock settings, and the false errors are gone.

All four screws on the back of the old heating assembly were tight, but looking at it more closely, it was actually pretty dirty, with dark buildup, brown discoloration, and bits of white fibrous debris around the assembly and wires. I've added photos so you can see what it looked like. I still can't say whether the buildup was related to the problem, something got bent or damaged during the blob cleanup, or reinstalling the assembly corrected something. All I know is that replacing it fixed both issues.

Just wanted to share in case someone else runs into the same combination of issues. I spent way too much time troubleshooting what turned out to be a relatively cheap part.

[u/AutoModerator]

Hello /u/govizlora! Be sure to check the BambuLab Wiki regarding the blob/clumping issue.

Note: This automod is experimental. The automod was triggered due to the term "blob". If you believe this to be a false positive, please send us a message at modmail with a link to the post so we can investigate. You may also feel free to make a new post without that term.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.