H2S Downtime due to failures

Bambu Lab H2 Series
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Frustrated with Bambu Labs customer support. I am now on day 59 since September of 2025 where my Bambu H2s is sitting like a brick waiting on parts from Bambu to fix the issue. This current issue has been ongoing since April 4th (previous issue was Jan and took over 25 days to resolve) and I’ve had to go through the replace a part at a time before they finally decided to send an entirely new rail assembly. This was supposed to happen on May 4th, no part has been delivered. I track the part and it shows still at the origin shipping facility. I have to notify Bambu its stuck and now I have to wait 3 days for them to investigate before they decide to send a replacement rail which would take another 10 days from the time they decide. I will be lucky to have a part by the 24th on something they said they’d send on the 4th. This is ridiculous.

They send free printers to youtubers yet for those of us who have spent over $3200 on printer, AMS, and spare parts we can’t get a replacement for an obvious dud of a printer that has been down for over 25% of the time of ownership. Not asking for anything free, just asking for a working printer to replace the non-working POS I was delivered. Also asking that I don’t have to keep wasting my time to do their maintenance on one of the worst printers for maintenance that has ever been designed.

All the bambu fanboys can save your comments for yourself. I love the printer when it works and want to keep using Bambu. But it’s hard to justify when you pay that much for a printer, have to do the repair work yourself, deal with a customer service that only replies once every day or two and then takes 10 days to ship a replacement part. I’ve purchased most of the parts myself off the site when they are available but a lot of the parts are often out of stock (hot end fan anyone….).

Then Bambu customer service keeps saying be patient but when they finally agree to send you the rail you immediately get an email saying this is a high priced item and they expect you to ship back the bad unit within 14 days. Along with this 14 days you have to send a video proving you sent it back or it could impact your warranty and blah blah blah. So they want us to be patient but then send a strictly and often threatening notice about sending back their units in a quick manner with video proof. Go pound sand bambu.

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Didn’t you already say something about this on another thread?

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I replied to a thread that was older and over a 100 replies and had a different theme so yes.

This was its own thread in case other H2S owners have the same issues. So why is that a problem?

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I am at the stage where I have to kiss my H2S’s ■■■■ to get it to start printing. Then the constant damn spool bindings in the AMS2!! That is frustrating. Now the AMS2 is not seeing the RFID tags on the Bambu filament. That was working earlier today and then one by one each slot forgot what filament was in it and could not read the RFID tags. Yes, I cycled the power, which seemed to caused the RFIDs not to read.

I have been dealing with the filament jamming and not loading in to the extruder. Sometime it would get stuck in the buffer (and why the heck on the inside where it is difficult to service??), or at the top of the extruder. This started happening when I started using Bambu Labs Basic PETG. It may have been caused by a dull filament cutter, but that is only a try right now. Feels sharp to me.

I agree it is difficult to communicate with tech support and they intentionally make it a pain to do so “What is your serial number, send picture, …”, even though they have it under my name from previous tech support the week before. The it is a day in-between responses. I almost understand that. I would guess they have been selling a LOT of printers lately and there are growing pains.

When it prints, it prints pretty good. I do not thinks it like PETG very much. It prints PLA and ABS much nicer and with less complaints and problems. My POS Creality K2 Plus, prints PETG better than any other filament, and very well - lol. It is one has a lot of issues of its own, but once it starts, it is very fast.

Sorry, I am blowing off some steam here too.

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No problem, just confirming.

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I feel your pain! When my 4 AMS units work; it’s spectacular. But sometimes there’s just a print or filament that seems to just want to blow up the AMS for a day or two and then magically it works again. But I’d take that problem over not having a printer for the last 40 days. Ugh.

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Hey everyone, I just started printing four months ago using a H2D as my first printer. About 2-3 months ago I started having a issue with my left nozzle. I was running multiple batches of a two color print (simple “P” embedded in a circle) for a logo for a local company. I noticed that the “P” would print first using the external spool through the left nozzle, no big deal. Problem I am having is that my left nozzle would all of a sudden not print the purge line on the edge of my plate and also miss the first 1-2 inches of the print, resulting in me having to toss 1 of the "P"s off every plate (see pic for the discarded "P"s). I have an open ticket up with tech support and have been around the block with zero resolution. I am hoping someone in the community has had this problem and has a solution. Any ideas, help will be greatly appreciated!!!

If the AMS is used first, the purge line is perfect!

If I swap the external to the right nozzle, the purge line is perfect!

They have sent me a replacement buffer and I have replaced it.

Things I have tried:

- Tried flipping filament between the AMS and external hanger, no change.

- Tried different brands of filament, no change.

- Changed out the nozzle with a brand new one, no change.

- Changed the nozzles between left & right, no change. From what I can tell, all the nozzle temps, pressures, speeds, etc are the same (checking on the filament settings).

- Tore apart the entire nozzle to inspect if the gears were worn, damaged, clogged, etc, nothing noticed.

- Ran every calibration, bed leveling, etc on the printer after.

- Tried a different file that has some of the same two color printing

- Tried flow rate calibration

- Tried first layer adhesion calibration

Tests:

#1 - I ran on the left nozzle with the PLA filament running directly into the left nozzle with no tube in between, GTG purge line was awesome!

#2- I ran the left nozzle with the tubes reconnect, NO GO, purge line was same as problem

#3- I ran the left nozzle with the “left nozzle” tubes but “re-plumbed” to the left nozzle but the top wall port, GTG purge line was awesome!

#4 - I ran the left nozzle with the “left nozzle” tubes but in the bottom wall port, NO GO, purge line was the same as problem

#5 - NO-GO External spool routed to the LEFT nozzle via the BOTTOM buffer AMS spools routed to the RIGHT nozzle via the TOP buffer

#6 - FAILED to finish External spool routed to the RIGHT nozzle via the BOTTOM buffer AMS spools routed to the LEFT nozzle via the TOP buffer Swapped the PFTE tube connected at the top of the extruder. Re-mapped AMS to left nozzle in printer settings. Print “failed to feed filament” error multiple times. AMS would not feed through the buffer (could see it enter the buffer on the rear but never exit via the inside port).

#7 - PASS External spool routed to the RIGHT nozzle via directly into top of extruder (bypassing the buffer and all PFTE tubes) AMS spools routed to the LEFT nozzle via the BOTTOM buffer

#8 - PASS (full purge line on edge of bed & NO missing start of print) Redo of Test 5, only changed the routed of the external spool though the PFTE tubes and TOP buffer Current setup: AMS routed to LEFT nozzle via BOTTOM buffer, external hanger routed to RIGHT nozzle via TOP buffer

#9 - Swapped AMS & External spool connection at REAR of buffer External spool routed to the LEFT nozzle via the BOTTOM buffer AMS spools routed to the RIGHT nozzle via the TOP buffer NO-GO, same problem as before

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Just did a print, overnight although it was not a real lone print, with Bambu Labs White PETG. Got up this morning, with the print finished, but a “Failed to Retract filament” error. I can pull the filament out by hand, without heating. The extruder knob rotates CW, like it’s push the filament out. It thinks there is filament in the head. I take the extruder apart and there is nothing there. This time, the filament is cut fine (changed the blade yesterday). Funny thing is, I can get the same fricken error on my Creality K2 Plus, but there it is just a week CMS motor or weak extrusion motor, I don’t know which, but give it a little hand and it’s fine. On that printer, it weirdly does not affect multi-color prints, just when it is done printing. On the H2S, this has been plaguing my multi-color prints (which I do not do a lot of). I changed the nozzle last week and made sure the extruder is nice and clean inside. I don’t think it is the filament sensor. It knows when it gets filament, it just doesn’t seem to know when the filament is not there.

This printer is getting very frustrating to use and this all began when I started using Bambu Labs BASIC PETG. In the past, I always used what ever I found on-sale at Amazon or ESUN on the X1C and the K2 Plus without issue.

So, I dunno, maybe BAMBU LABS Basic PETG is not good filament, or the HS2 just doesn’t like printing with PETG. Of course, I have no idea why bad filament would cause was I have been seeing.

Since the AMS2 is intermittent at auto-detecting Bambu filament RFID tags, maybe I try some off-brand PETG filament I have in the closet.

I just find it hard to believe, on YouTube, print farm people getting on there and saying they have thousands of hours and zero problems with their H2S machines. They were given the printers early on, before mass production, by Bambu and probably have all engineer hand built perfect machines.

At this point, I am loosing confidence in Bambu printers. I really doubt, I’ll spend $1300 on a premier printer when I see how nice cheaper ones seem to be from Bambu and others.

Up until recently, I had thought of the K2 as a toaster, an appliance. For the last two weeks, it is now a 3D printing experiment, that I cannot trust. I am really disappointed in it.

I am going to open up a ticket with tech support, but I expect subterfuge in the first couple of responses, and maybe in about a week getting a good answer, maybe…

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Your filament detected error is essentially what plagued me and has now caused me to be down since April 4th. Per support I’ve replaced the sensor 2x (no joy), made sure there was a new official bambu cutter blade (no joy), replaced the board on the head unit (no joy), after breaking the sensor cable and part camera I replaced those and did a complete re-connect of everything else (no joy).

The next step is the complete rail system they are sending which should be a fix unless the problem is in the units main circuit board (ugh). I’ll tell you when it arrives next week if that fixed the problem.

On the print farm side, I truly believe this unit is either great or not great. Maybe it’s only 1 out of every 10 units that sucks (we are the lucky ones) but when they suck, they suck bad. I have an Elegoo CC, Elegoo N4Plus, and a new Kobra X and this H2s has far and away been the one that has had the most downtime and problems. It’s the best printer when it’s working, but being down over 25% of the time and increasing isn’t what we paid thousands of dollars for.

Will E.

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Don’t tell me that. I hate repairing the hot end where I have it mounted. I have to find a place for the AMS, then take the glass off and then it is just a tad too high (on my desk) that I almost need a step stool. I was thinking about replacing the filament sensor, but it does seem to know when the filament hits the hot end. I know, it used to know, when the filament ran out.

Yes, that sensor looks like a pain the ■■■■ to change.

Why would your rail cause a filament sensing problem? That seems like a MAJOR PIA to get out of there and replace! The belts alone for be really bad. I would think it would be easier to replace the main computer board. Take a picture and then un-hook all the wires and cables and replace the board. What, about half an hour, compared to 4 hours replacing the rail and print head?

This fxking toaster has become a headache and now an experimental 3D printer.

“Elegoo CC, Elegoo N4Plus, and a new Kobra X and this H2s”

Hasn’t Elegoo just come out, or is about to release a four head tool changer at a great price. There is one company that I saw on Youtube which will have or very soon with a full enclosure and chamber heater for like $850-ish? Their system, awkwardly tall, looks a lot simpler than the H2C. I don’t think they have an AMS for the filament. Four rolls just mount on the right side. I pretty much have low humidity here in the shop year around, so that is not too much of a concern. But… I like the build volume of the H2S. That is why I bought it. If I did a lot of multi-color, I would have gotten the D or C (or what ever the letters are).

Meanwhile the X1C chugs along with hot end I haven’t had to replace in so long, I’ll have to hit the wiki to remember how.

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ha, good question. I have no clue why the rail system would be the fix and yes from looking at the videos it indeed looks like a PITA to change! Of note though, the rail comes with a fully assembled extruder and etc., so maybe they are doing it so I don’t keep screwing up the connections and etc. :slight_smile: That’s all I can figure out.

I also believe it’s just their way of going down their troubleshooting checklist of replace until it’s fixed (much like car mechanics)..keep replacing sensors until 1 fixes it!

I think it’s flashforge coming out with the $850 tool changer unit. Elegoo just figured out how to do the Centauri Carbon 2..I doubt they are that far along on more advanced technology!

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It is probably flash forge.

I was never bother by filament waste. It really doesn’t cost us much money, more time than anything. Then when the toaster I rely on thinks it cannot retract the filament, when it clearly does, that becomes a huge problem for multi-color, or dedicated support filament.

I looked at the instructions for replacing the filament sensor, which I really do not think it the problem, holy crap, it looks so easy to damage a lot of cables tearing that entire extruder head off to change that sensor. To make it worse the sensor is the Boden tube connector. So you leave the part cooler and part camera dangling on their delicate cables while tearing the extruder off to change that sensor? To Paraphrase Yaakov Smirnoff “What a company!”.

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That looks cool, but isn’t having the spools external and not in a troublesome AMS2 not good?

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Be warned about FlashForge I have had nothing but issues with my AD5M and I would stay away from buying anything from them. According to a darth Vader OP all of this you knew when you bought this right? I mean why complain about service and breakdowns this is a hobby and Bambu is the best….LOL right

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I had the GD extruder apart, again and the filament sensor apart. Nothing jammed in the filament sensor. Drop one of its tiny screws inside the printer, with front door closed and never found it. I ran my Fanttik vacuum all through it and never found it, so I guess it went through a black hole. There was some stringy blue PTEG in the gears. There is no sensor there, so I do not understand how that would have triggered the pull the filament out error.

It went through its testing and started printing again.

I am taking all 20 rolls of Bambu BASIC PETG I bought and throwing them in the trash barrel; that filament is all crap! These problems all started with that Bambu Basic PETG. I’ll go back to SUNLU PETG and INLAND. No RFID, No Refills, but they work. The cardboard spools work great with the CFS on the K2 Plus, but typically do not fit well in the AMS. I am not sure about the AMS2.

I was right about the support response: “send a detailed video of the failure”. The rest was the typical subterfuge. There is nothing to show! The damn thing never gets to the point of movement, it just error before it gets that far. I guess I could video the LCD showing the error. They ignored my complaint about the AMS2 not picking up the RFID tag, especially in slot 4.

So the lesson in all this? Get on Amazon and order of bunch of good PETG from Elegoo or Sunlu and throw away all that lousy Bambu Basic PETG. I will never purchase PETG from Bambu again. When it does print, the results are not optimal. I use Bambu’s built in parameters for their own PETG and I am not playing with them. This is a fracking toaster I want to reply on, not a damn science experiment. I guess I should try that Bambu PETG on the K2 Plus. It seems to print with everything. My main complaint with it is the motors in the CFS are weak and a print often ends with a failure to retract (similar error to the H2S), but it is always if I pull the filament and give the CFS a hand, it works. If I use the external spool that never happens. Their slicer is also pretty dumb. It does not slow the print down for transparent PETG and the print always turns out acceptable. Now it never prints as good as the H2S or X1C. I had a large format printer that did a lot of work for me here in the shop a year or two before Bambu had the H2 Series, or I would never have purchased a Creality product.

EDIT: The print just failed with a spagetti print. Never had that before on the H2. This was with White Basic PETG from Bambu after being dried all night. Okay, probably my bad for not washing the print bed with ISO. My hand were probably on it after work on the print head.

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Thanks for the update..I didn’t see anything in my gears but now I will look closer! Good luck and hopefully this doesn’t happen again!

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I swear it is lousy PETG from Bambu. They probably get their filament from the lowest bidder. I do like the RFID tags but they don’t work that well.

That said, with the strands of filament in the gears, even though it was different color from the print I just did, did it detect that it was harder to turn the gears that it should have been? I do not know. My other thought is that the cable from the Filament Sensor to the back board is intermittent. I have to pull the sensor out every time I take the extruder gear cover off (that is a bad design to have to do that with a fragile flex cable like that, just to get the gear cover off).

Replacing the cable for the filament sensor looks a real pain in the buttocks. You have been through it. Their guide says 20 minutes, but how much damage to delicate cables can be down? What you just leave the camera assemble hang by its cables while do the other work? What crap of a design.

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I can feel your pain. Hey I am taking a survy. So how many of you folks knew that you would be stuck fixing your printer on your first buy? According the our Darth Vader friend this is widely known knowledge.

I do however know that is is the fact that you will be fixing these. I imagine that feeling cam from everyone just buying these with the perception that they would not fail as much as they do. I guess what really is the problem, the fact that they are not built that well. Maybe that’s a price thing but I am willing to bet if you buy a large commercial machine: 1, there would be service and 2. built very well. As long as the buying public continues to buy then this will never be addressed. I challenge Bambu, Flash Forge and all the other brands in their advertisements to state that YOU will have to fix these machines. Be right up front and let see how that goes….

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I went over it in my head before I purchased, 80lb package shipped from china, tons of fragile electronics, plenty of people discussing making repairs, good chance it could have problems.

Boxing it up and shipping it to be repaired would be a major pain for me and likely and major expense for the manufacturer ,So I figured 50 50 chance I would have to work on it my self if it failed.

I researched the major brands and got the same vibe from all of them and came to the same conclusion, I will likely have to keep this machine running because the likely hood of Bambu Labs sending a helicopter to my house to pick it up and take it to the airport and overnight it to china to be repaired just didn’t seem likely.

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I had a belief I’d fix some of it. But when you get a machine that is down over 25-30% (as of today 61 total days combined) of the time then you’d expect that there is a point of just replacing it. Elegoo did this after 25 days and 4 fixes didn’t solve the problem. My problem with Bambu is now since April 4th, nothing has worked, and they refuse to even consider just sending a replacement and having me pack up my old one in that box to send back.
I’ve seen the channels on youtube with influencers who didn’t buy the unit, it had major issues, and bambu just sent them a new one to replace.

So they can do it, they just don’t want to for people who pay for it and don’t have 20K youtube followers.

So again, the gripe isn’t doing some minor replacement, it’s having a brick for over 60 days and Bambu only says, well, here’s the next box in our troubleshooting and oh, you’ll get the part in 7-12 days. Mind you, if I buy it off their website I get it normally in less than 5.