Hi there,
My AMS primary feed motors (the 1st motor in line between the spool and the output of the AMS) works fine. The 2nd motor at the output of the 4-to-1 hub inside the AMS, is not running. The 1st motor and feed pushes the filament while loading, but then it hits the 2nd motor feed and stops and the 1st motor just grinds.
It’s all been inspected - the filament path is clear in each of the 4 AMS channels - i’ve tested them all and same result. It would appear the 2nd motor, or motor-drive has failed. Worked perfectly for the first 5 prints, from new, but then failed.
Everything else in the printer is working fine… but the AMS is dead.
Submitted a support ticket and had some things suggested by Bambu - it all checked out with the exception of not being able to make it run.
There is no resolution, and SUPPORT went radio-silent for over a week now. Clearly this needs to be a warranty repair or replacement but nobody is responding!
Anyone else have this issue, and any suggestions I should try or test, before I take this lack-of-support to social media?
Sorry you’re fighting the system. BL support is pretty overwhelmed right now and they’re working on training new support staff. Sadly, that takes time … Not of course something you want to hear when you’re frustrated.
Now - to your problem - Have you disassembled and checked the wiring?
Obviously, do this with it disconnected from the printer -
I’d carefully unplug and re-plug each of the plugs inside the AMS. If you’re concerned about opening it, don’t be, BL doesn’t play the “open it and Warranty is void” game. Unless of course you mangle it …
It may just be a loose connection.
Also you might read these two threads. It doesn’t directly discuss your problem but it will give you some insight into the AMS and it’s issues.
Hi there and thanks for the quick response. yes - I have gone back and forth through a Tech Support Ticket.
yes i’ve checked the wiring - all the external and internal connectors going to the motor, hall sensor module, etc… there are 3 of them that go to the hub. Checked, removed, re-seated.
yes i’ve checked for stuck or broken filament or plugs. All clear. disassembled the hub to ensure it’s clean and parts are moving freely. they all are.
yes i checked all 4 spool positions in the AMS - all work fine, spools move freely etc etc. The spool feeder ifself runs fine… but when loading the filament - when the filament gets to the 2nd motor, it stops because the 2nd motor does not begin to spin… and so the filament feeder motor just grinds away and carves out a groove in the filament. After a few seconds it retracts - the red LED flashed a few times, and then the process starts again… runs that way continuously until I either remove the spool and filament manually or turn off the printer.
No issues opening up the AMS. Totally comfortable doing that with the mech and elec parts - 30yrs of aerospace design and test engineering (both mech systems and avionics electronics)… so inspecting it all is totally easy for me.
Unfortunately I found no issue visually, that I could easily fix.
it would appear either the motor itself, or the motor-drive circuit on the AMS control board, has failed.
Initially the tech support was excellent. Response every day, as we walked through the steps to troubleshoot. But then we got to the conclusion that something has in fact failed… and some sort of warranty repair or replacement is evidently necessary, all comms stopped… that was 1 week ago! I’ve been asking every other day for updates… radio-silence.
All I really need Bambu to do is send me a motor, or the control board (the motor drive is on the main control board), or send both. I can switch them out myself. No need to bog down your service / warranty shop, and the cost will be minimal for both Bambu and myself (in terms of shipping)… and the fastest fix (only 1 way shipping). I have an ESD protected workbench to ensure all the sensitive electronics do not get damaged. I’m ready to go!.. But… I got no response!
And to be honest, there is no clear “warranty support” page that I could find on the bambu website, to initiate a basic warranty claim… all there is, is tech support and general inquiries…
it’s not a big deal if this needs to be worked through the tech-ticket method, but when I am getting no responses, it’s very frustrating… AND the warranty clock is ticking!..
Yeah, I think you passed the job interview. It’s so funny the range of people you meet in here, some couldn’t tell the pointy end of a screwdriver.
Longtime Tech myself. Used to have a badge for the Cape to work on Lockheed - Martin’s computers there, and the Scheduler for the Shuttle. She was a hoot, I arrived one day and watched in shock as she threw the head of NASA out of her office to talk to me. He laughed. Good times.
Sorry to hear your pain. The ticket system is their Warranty claim system. They may be slow but for the most part are really very good about claims.
I wouldn’t be too concerned about timing, you’ve already started the process and they’re very aware their system s*cks.
Here’s a recent Blog post, interesting reading.
BTW - Re-reading your description of what was done triggered an odd thought. All this stuff is hooked with JST connectors. I had an absolute nightmare fix once that was sooo subtle. One of the connectors inside the JST had pushed back. You really needed to look to see it.
I doubt that’s it since your description flat out fits the profile of the very complex “the motor is FUBAR”, but if you get frustrated enough to try again on the inspect …
Next time you talk to them you might suggest a whole new AMS instead as a reward for your “patience” . Might actually be easier for them they may not have the stupid motors!
LOL!.. yea thanks!
Yea we did some work on both the F22 and F35 for LM… and the X33… remember that one?
I dismantled the unit once again and put on my 5x magnifying glasses on to see if I can spot any soldering defects, or other minute physical damage on the various SMT components and the connectors. All good from what’s visible.
I checked those connectors and wires - its the 1st thing I did. But am going to spend a bit more time on that one, along with some tests.
The motor seems to be either a stepper motor, or multi-phase AC motor (6 wires), or may have a resolver built in - but it doesn’t really look like it has a resolver - from an external mechanical appearance perspective. Most likely a stepper. I may put my scope to it to see what kind of signal I see… or if the signal is missing.
I’m going to take the gear off the drive to see if it wants to move under no-load. The hub spring-loaded tensioner exerts quite a bit of pressure on the motor and gear train once the filament feeds in…driving a bunch of friction. The size of the motor tells me it shouldn’t struggle with that, but you never know.
I figured if I poked you with a possible solution you jump on it. The answer is always easy in retrospect. Type of motor - I’ve only looked at it in passing, so no idea.
Did you get this resolved? I have the same issue and have been dealing with support for 16 days now. This has been the worst support incident to date. Last reply from support was they were escalating my ticket to R&D.??? Not sure what R&D has to do with a bad second stage feeder. It’s a simple resolution. Send me the part. Bill me or free I don’t care. I just want it fixed in a timely manner.
I believe the issue is CMOS latch-up in some of the circuits, including the motor. R&D is invovled because that’s a design problem, and requires a design change to fix - it’s an easy fix though - but their design team needs to be involved.
Reason I think it’s a latch-up problem is because my AMS started misbehaving in a big way as I was performing various test and troubleshooting activities - all 4 1st stage feeders started flashing red after power-up. The whole thing stopped responding completely. I then - on a suspicion - did an “old electronics trick” used to deal with CMOS latch-up… something I learned early in my career - from back in the 90’s… and the AMS recovered. It led me to my general conclusion.
Please don’t ask me what the trick is, because unless you know exactly what you’re doing, you will 100%-guaranteed destroy the board, and be far worse off as a result.
Keep in mind that not all 2nd stage feeder problems are the same. I take it you disassembled the whole drive unit and hub, to ensure there aren’t bits of plastic stuck in various places?
Anyway - they sent me a new board and it’s working now.
Hellow @wally.malicki
I have exactly the same problem you have. Your description of the problme maches 100% with my problem.
I am also a old fart. Electronic engineer, and, coincidently, also worked in aerospace.
Please, send me the trick to deal with CMOS latch-up. I can do it.
This sounds like what is exactly happening to me right now. I can’t even manually push the filament past the second motor without manually turning the gear. Once through I can push to the toolhead. Very strange.
add me to the list, printer/ams less than a week old. maybe 40hrs of print time. finished print and it wouldn’t withdraw the filament, flashing red light. took the ams apart to get the filament out.
Same problem here. Had the AMS for less than 2 weeks and mid-way thru a multi-color print it stopped and gave the failed to feed to toolhead error. Went thru the wiki and got to the part where it recommends re-plugging in the motor cable. No Dice. Filament loads up to the internal hub then gets stuck and second motor won’t turn.
There was the same breakdown a week after buying the printer. I created a ticket for this problem and, under warranty, they sent me a hub motor and an AMS hub to replace it. After the replacement, the AMS works stably.
