Another Bambu Lab A1 Malfunction

In October 2024, I wrote about my Bambu Lab A1 3D printer heatbed temperature malfunction. Because the malfunction occurred within the 30-day replacement window, I was able to return the printer and have a replacement printer sent to me.

I have had a great experience with my replacement Bambu Lab A1 3D printer until November 2025 when I started witnessing that the printer would randomly lose all power. Sometimes it would happen during the pre-print routines (e.g., bed leveling, bed heating, filament purging), and sometimes it would happen in the middle of a print. Despite the main power switch remaining in the ON position, the printer would lose power, the fans would turn off, the screen would go blank and unresponsive, and the Bambu Studio slicer would lose communication with the printer. Initially this occurred infrequently, but it seemed to occur progressively more frequently over time to the point where most of my prints would fail due to unexpected power loss.

Because of the prior heatbed temperature malfunction in October 2024 and the current power loss malfunction in November 2025, I have started to question the durability of Bambu Lab 3D printers. Nevertheless, I bought another Bambu Lab A1 for three primary reasons. First, I enjoy participating in the Bambub Lab ecosystem where things just work (that is, until my printer breaks down). Second, I have meticulously set up air purifiers both inside and adjacent to my Bambu Lab A1 third party enclosure and didn’t want to re-configure my setup with a different printer’s form factor. I had considered upgrading to the Bambu Lab P2S, but that will have to wait. Third, Bambu Lab was in the midst of their Black Friday sale, and the A1 printer was on sale for $279 (normally $399).

Meanwhile, I asked ChatGPT to help me diagnose the problem, in hopes that maybe I could acquire parts to fix the older printer. After describing my scenario, ChatGPT concluded that there was an 80%+ likelihood that the power supply unit was responsible for the power loss. The other possibilities were a loose power connector (15%), a mainboard power regulator failure (5%), or a firmware or software issue (<1%). It encouraged me to contact Bambu Lab Support and stated that even though my printer was just past the 1-year warranty period, they might still help me out. I had previously written about the Bambu Lab Warranty, and at the time I had focused on the language related to returns, refunds, and replacement within a 30-day window. Looking more closely at the general warranty language dated November 18, 2025, it also says that there is a “2-year warranty for for consumers from the EU, Switzerland, Norway and Iceland” and a “1-year warranty for the rest of the world (any country not mentioned above).”

I submitted a support ticket to Bambu Lab, and they directed me to the Bambu Lab Wiki for “Printer Circuit Failure Troubleshooting - A1”. I confirmed that all indicator lights were in their normal status.

• The TH Board indicator light was constantly green
• The MC Board green light blinked every 5 seconds
• The AP Board had one green light blinking once per second
• The HMS indicator light was constantly on

Based on questions from Bambu Lab Support, I also confirmed that the fuse was NOT blown, and the power switch had good contacts and no corrosion. Also, I measured the AC power input at terminals #4 (neutral wire) and #5 (live wire) of the power module, and the multimeter reading was 123.8 volts—a normal value in the United States.

Bambu Lab Support asked me if the main power indicator light would turn off when the machine is powered off, and I confirmed that it did. They also asked me to confirm that the 24V power module indicator light was a steady green light (normal state) when the machine is powered on, and I confirmed that it was steady green. They also asked me to verify that connections for terminals #1 through #5 on the power supply were properly inserted, and as far as I could tell, they were. Based on this information, they decided to send me a power switch assembly and noted that despite my printer exceeding the 1-year warranty period, “This component is a special free replacement.”

To me, this gesture from Bambu Lab went a long way toward mitigating my frustration with my 2nd A1 printer malfunction in 13 months. Also, ChatGPT was correct in encouraging me to contact Bambu Lab Support based on a history of them supporting printers past the warranty period. Although I still question the durability of Bambu Lab printers, I must admit that I have received very good support that has exceeded my expectations.

However, one main question remains. Although ChatGPT seemed at least 80% confident that the power supply unit was to blame, Bambu Lab Support sent me a free replacement part for a power switch assembly which ChatGPT suggested was a much less likely culprit. I updated ChatGPT with my recent interactions with Bambu Lab Support and asked if they perhaps wanted to first have me replace the power switch assembly because it was a less expensive part, and ChatGPT agreed with my assessment. It went on to say that it still felt that the power supply was still the most likely culprit and suggested that I replace the power switch assembly as instructed by Bambu Lab Support and see if that fixes my problem. If I still experience power loss after replacing the power switch assembly, then that makes the power supply unit the only remaining rational explanation. ChatGPT communicated to me that this is probably just the normal troubleshooting algorithm they go through. Bambu Lab Support has not commented on their protocol, but the ChatGPT response seems to make logical sense.

So now I anxiously await receipt of my free replacement power switch assembly. I hope it fixes the power loss issue but realistically expect that I may have to reopen the support ticket and ask for further assistance, with possible replacement of the power supply as a result. Stay tuned for what happens next!

Maintaining and Troubleshooting My Bambu Lab A1

I purchased my Bambu Lab A1 Combo about 5 months ago, and with the exception of a heatbed temperature malfunction, I’ve had a great experience with it because the 3D printer just works. In comparison to my older 3D printer, the Bambu Lab printer is relatively worry-free because bed leveling, Z-height adjustments, and flow calibration are done automatically, and success rates with prints are very high. That being said, the printer does require occasional routine maintenance, and there are some common issues that I’ve either experienced myself or see reported by others that may require troubleshooting.

MAINTENANCE

First let’s talk about routine maintenance. I find it helpful that my Bambu Lab A1 reminds me of scheduled maintenance. For example, it tells me when it is time to lubricate the A1 Y-axis guide rail. It displays a QR code on the screen which takes you to the wiki page with written step-by-step instructions and an accompanying video to illustrate.

Another reminder is the availability of firmware upgrades. Upgrading is as simple as accepting the upgrade on the touchscreen or from the Devices tab in Bambu Studio. While most firmware upgrades are welcomed with open arms, there has been recent controversy with the impending release of their Authorization Control System which they state is being done for security reasons. Some users have lamented this forthcoming change, the rumor mill was in full swing, and Bambu Lab issued a statement to set the record straight related to third-party integration with Bambu Connect in an attempt to quell some of the fear. A summary is provided here and here and a zillion other places. Suffice it to say that I am not bothered by it at all, and I will likely just instal the firmware update when it becomes available.

Visit the A1 Maintenance Guidelines for additional recommendations.

TROUBLESHOOTING

Aside from the aforementioned heatbed malfunction, the main issue I’ve had to troubleshoot is related to filament getting stuck in my AMS Lite unit. One time this was due to a tangle in the filament (which was my fault for accidentally letting go of the filament and not checking for tangles when loading the filament), and at other times it had been due to an overly sensitive filament tangle detection feature which simply required me to resume printing (I’ve since deactivated filament tangle detection because of the high rate of false positives).

I’ve recently started following the Bambu Lab subreddit, and there are some common problems that people report. By far the most commonly reported issue is a sloppy or non-adherent first layer, and community contributors are always quick to point out that users have gotten the oils from their fingers onto the build plate. While some people use isopropyl alcohol to clean their build plates, Bambu Lab offers a Textured PEI Plate Cleaning Guide and specifically recommends detergent because alcohol might only spread the oils on the print bed rather than removing it. While some commenters swear by a particular brand of dish detergent, I find that any dish detergent or liquid soap does the job well, as long as I remain vigilant about not touching the build plate with my fingers after washing.

One time I introduced a jam in my hotend because I attempted to feed a new roll of filament into the hotend in the middle of a print job as I reached the end of another roll. I simply needed to understand how to remove the hotend so I could clear the jam, and sure enough there is a wiki on how to replace the A1 toolhead.

Perhaps less common but certainly very dramatic is when users experience hotend clumps. If left unattended for many hours, the clumping can turn into a huge blob. Although it may appear quite disastrous, Bambu Lab provides blob/clump cleaning instructions which should restore printers to fully functional status.

CONCLUSION

As with any hobby, there may be ups and downs. For 3D printing, maintenance and troubleshooting are inevitable, but I think Bambu Lab does a very good job of making it as understandable as possible. I hope your ups far outweigh the downs so that you can unleash your creativity.

Bambu Lab A1 Heatbed Temperature Malfunction

I’ve been enjoying my Bambu Lab A1 3D printer. Bambu Lab has done a great job of improving usability of the entire 3D printing process--this includes its MakerWorld model repository, its dedicated Bambu Studio slicer, its calibrated filaments, the Bambu Handy mobile app, and of course the speedy 3D printer itself. Everything just works the way a 3D printer SHOULD work. That is, until it doesn’t.

A couple weeks ago I started to see “Heatbed temperature malfunction” error messages as pictured above. Initially these errors would appear after successful completion of 1 print job and upon the initiation of the next print job without turning the printer off. After pressing the “Confirm” button in Bambu Studio or dismissing the error message on the touchscreen, I would see that the newly initiated print job was suspended in a paused state. After pressing the resume button on the touchscreen, the heatbed would proceed to warm up to the specified temperature (usually 65 Celsius), and a successful print would ensue. I was hoping that this error message was due to a firmware or Bambu Studio software glitch, as I had recently updated both.

However, after several days of encountering intermittent “Heatbed temperature malfunction” error messages in between print jobs, I experienced this error message in the middle of an 8-hour print job, and upon dismissing the error message and resuming the print, the heatbed remained at room temperature. I was concerned about the print falling off the build plate (because warmer temperatures help the printed materials stick to the build plate) but fortunately I had excellent bed adhesion, and to my pleasant surprise, the print successfully completed anyway.

Upon reporting this issue to Bambu Lab Support, I was asked to troubleshoot the heatbed issue by following these instructions on the Bambu Lab Wiki. After purchasing a multimeter and asking ChatGPT how to use one, I was able to confirm that the resistance measurements of the temperature sensor connector and the heatbed power supply connector were both abnormal. According to the wiki, “replacing the heatbed assembly is necessary if both resistance values are abnormal.” So I thought Bambu Lab was going to ship me a new heatbed assembly and I’d have to follow these instructions to replace the heatbed.

Instead, Bambu Lab Support offered to continue troubleshooting the issue by first sending me a new AC board, which contradicts the recommendation from the wiki, or to return and replace the printer because I was (barely) within the 30-day time window after receipt of the 3D printer. Since I am not knowledgeable about electronics, I decided to return and replace the 3D printer and had to follow these instructions to pack my printer. Because I bought the A1 combo which included the AMS Lite unit, I had to return the whole set—this seemed wasteful because the AMS Lite unit was working fine. Anyway, the photos and videos were helpful, but if there was one thing I learned from the experience of packing the printer and accessories, it is that it was extremely important to have saved the original box and all of its packing materials, including the plastic bags and protective foam pads and cardboard inserts.

Bambu Lab provided a UPS shipping label and informed me that “the return process can take around 2-3 weeks, depending on the shipping conditions” and “the replacement will be arranged within 7 business days after the warehouse receives and inspects the package.”

Overall I wish it was a little easier to troubleshoot 3D printer malfunctions, but the Bambu Lab Wiki made the process as simple as it could possibly be. Perhaps a better approach to support average everyday mainstream users would be to have dedicated Bambu Lab service centers, but of course there would have to be a business model to make that happen. Because I purchased my 3D printer from the online store, I had no choice but to work through the online support process. Had I purchased the printer from an authorized reseller, I assume that I could have returned and replaced the printer in the physical store, and I wonder if I could have avoided all the troubleshooting and packing steps. Unfortunately the nearest reseller is about 50 miles away from where I live, but if you live near a reseller and are thinking of buying a Bambu Lab 3D printer, that option may make more sense.

Anyway, I hope my replacement A1 Combo will arrive soon and that there will be no malfunctions with my replacement device.