Hms_0500-0300-0001-0002

Bambu Lab P Series Troubleshooting
1

And in my darkest hour I request your support…

Well, 3 weeks ago I have installed the upgrade kit on my P1P. Bevore that, the machine performed flawlessly. No errors, so stuckups, working like a swiss clock…

I took my time. I followed instructions from the bambulab wiki. I didn’t took any shortcuts mounting the upgrade parts…

Well since then, my printing life has been an horror:

First 4 runs, 10-20 Minutes after printing started, the machine would freeze without any reason, would not react to any commands, except the for light ON/OFF.

Later, the printer after being powered on, showed the toolhead error message: HMS_0500-0300-0001-0002. I checked, and rechecked the toolhead and the MC-Board connections. It didn’t help. I contacted support, in hope of getting assistance…only to be getting asked around for about a week of checking and re-checking the boards LED behaviour, the cable, connections…as if I didn’t do it myself 3 times already.

After finally a week later receiving replacement parts, and trying to fix that thing, I am almost close to giving up…

The actual situation:

I have upgraded the machine to the P1S, selected “Installed the official upgrade kit”

After the error I have replaced:

-the toolhead boards, the ribbon cable between the front- and backboards - received from support,
-the toolhead-MC cable - received from support
-today, the AP Board,

The error still persists!

Today also I have ordered a replacement AP-MC cable.

If the bloody cable arrives, will be mounted and the error still will be there, I’m going to cry…

So, now the question for the community:

Have anyone encountered similar troubles?

I have replaced almost everything electronic except for the Camera, the front panel, the heatbed, the stepper motors and the power supply…

Any input would be appreciated…

Best regards:

wladi92

2

I know nothing, but reading your message makes me wonder if your software update glitched and was corrupted. In the same situation I would get a new memory card, reset to factory settings and retry the update.

1 Like
3

Nice idea…have done that already…have formatted the original Lexar SD-Card, and the fact that I have replaced the AP-board today and the error still persists lets me think about an alternative source of error…

The only thing I have not replaced in the chain of error sources affiliated with the message is the MC-AP Cable…yet.

My questions resulting from that:

-Does anybody know the pinout of the AP-MC Board cable? May a single pin be defective and creating such an exotic error?(Occured while chaning the TH-Cable)
-How high are the chances of the AP-MC Cable being the culprit?
-Is there any chance of an overvoltage being carried over?
-Is there any chance of the two same parts from Bambulab being defective?

Addendum: is there a chance of the latest firmware update being the culprit? Is the MC-Board also being updated while the firmware update is being installed on the printer?

Regards

wladi92

4

I’m not sure either, it might be your firmware.

5

May I assume you visited this wiki?

I can say this: even the most experienced person can misalign the connector, and you would never know by feel alone because it gives a positive “click” when snapped in, making you believe it is connected correctly. However, when this happened to me after upgrading my P1P, I consulted this photo and found that it was exactly the problem—I had the same error as you. It turns out the connector is not keyed, meaning it can be misaligned by an entire row of pins, with one row sitting outside the connector and you would never know it. You can’t rely on feel; you have to look at this photo and compare.

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1 Like
6

You may have multiple issues you’re dealing with (hardware and software), but if you haven’t already, REPLACE that micro SD card with a new, high quality, name brand, freshly formatted card purchased from a trustworthy seller. There are a lot of fakes being sold online of dubious quality.

7

I had the exact same issue. I ended up uninstalling the upgrade kit, putting everything back together. I have replaced basically every board. I finally got the error code to go away by replacing the TH Board Cable- it has been a disaster once that was fixed. Things were great until I changed out a nozzle and I’ve been chasing a print ever since doing a basic nozzle change again every time I fix one issue another one arises.

Good luck it’s exhausting when trying to get troubleshooting and everyone keeps saying the same stuff to check the pins I spent days checking the connections feeling like a crazy person.

Support offers no help

8

Yes, I have. I actually can recite the whole page.

Trouble is, the error comes and goes as it pleases. Sometimes, the printer works fine for 1-2 days, than - again - stops reacting to any commands. I check all the cable connections and somtimes after first, sometimes after 2nd, 3rd try the message goes away…if there were some kind of “continuity test”, by which the machine would signalize why the error appeared and what exactly is the source of error - no data from the thermistor for instance…

I’m a trained IT-technician - by german standarts. Such errors are most hated because they are “swimming” or “non-replicable” - you don’t get a feeling why or when the error is appearing.

Best regards

wladi92

9

I have replaced the card with a brand new 265GB SanDisk extremePro, fresh out of OEM Packaging. I will report back when support “unlocks” my AP Board and the firmware can be updated…for now the board appears locked until registered by support.

Best regards

Wladi92

10

Thanks. I had the feeling that I was slowly losing my sanity all alone.
So do I understand right that even after you have fixed the machine still a number of errors remained? Or did it go away after sucessfull identification of error source?

I have - for now - ordered a new MC-AP Board cable, it is the only one I havent replaced in the control circuit yet…

If there would be some schematics or some measurement protocols like in use at analogue devices(ex. “P08 has 4,5V DC compared to GND of the board”) I could at least try to identify the error. So, to understand and draw the electronic schematics by myself would take months…

Best regards

Wladi92

11

Here’s something you can try—it worked for me when I was dealing with spurious errors.

What I’m about to describe defies logic—except that it was the only thing that worked for me when I was getting a similar error claiming the toolhead cover had fallen off. I spent over $100 on parts trying to fix the issue, and nothing worked. Then, on my 20th attempt, I left the screws out of the back cover, expecting I’d need to remove them again anyway.

After a week of flawless printing, I reinstalled the screws. The problem came back immediately. I removed them again, tested, and the problem disappeared. I repeated this process five times and was able to reproduce the error every single time. So now, I run the printer with only the bare minimum of screws to keep the cover in place.

I was pissed at all the money I wasted. This was one of the few times I actually contacted Bambu Support, and they completely failed me. On top of that, they bullied me into upgrading my firmware—even though I explicitly told them I didn’t want to. They flat-out refused to answer any more questions until I upgraded. Once I did, the issue persisted, and I was locked out of back-revving because Bambu’s attitude is basically “Pound sand.”

Here’s what my printer looks like now—trouble-free ever since:

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I have no screws in the center shroud, it is only held in place by friction and clips. My theory is that the PCB may come under stress and as a result, the hall affect sensors were being mechanically stressed or the PCB was being stressed. Your error may be suffering from something similar. It’s worth a try.

To borrow from Sherlock Holmes:
“When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

HMS_0300-0300-0001-0001: The hotend cooling fan speed is too slow or stopped
12

Okay, I made a new observation: While sitting(bad mooded of course, my friggin’ printer is out of commission) I, just for fun, tried to toggle the 3 fans on. No reaction. After letting it sit there for approx. an hour(!) suddenly the fans came to life! I could toggle them off instantly, toggling on took again approx. 20 Minutes!

Even stronger and stronger I have 3 possible suspects:

-Bad/Cold soldering points(but then why work/ not work sometimes)
-defective AP-MC cable(again why work/ not work sometimes)
-Bad Firmware(Again, why such specific circumstances? All I did was to apply the upgrade kit which is composed for 80% of cases and lids and not additional electronic hardware!)

@Olias Thanks for the idea, as soon as support have unlocked my AP Board I will test your theory…I was afraid that we would, somepoint in time, get to the esoteric part of fault search…(no offense meant, I know exactly what you mean. Sometime it just works when there is lights off or the cable is twisted in certain ways…)

13

You magnificent bastard!

Be happy I don’t know where you live, otherwise I would kiss, or at least hug you!

I pull out the last bloody screw out of the hole provided by your pictures - the very f***** second the error vanishes!

I will check up on the source of error, I will think and test why there is such an…unorthodox…connection between error and source.

How the P1S case and the error is connected… I possibly will consider asking a vodoo man.

For now, thank you!

P.S.: I will test around for a few days to be able completely confirm up on your solution, after that I will mark your answer as such!

1 Like
14

I’m delighted that my suggestion may “appear” to have worked. As the saying goes, “even a broken clock is correct twice a day.” :smirking_face: But don’t pop the champagne corks just yet. Run it for a week, and then, just to be sure, replace the screws with the intent to cause it to fail. I know this sounds counterintuitive—why mess with something that’s working? However, this test-to-destruction diagnostic method is something I’ve used effectively in my day job for over 40 years to ensure I know exactly what can go wrong and how.

Theories

On the subject of why, that’s why I suggest the extra step. I don’t run my printer at very high temps often. My usage of PC to PLA is probably around a 1:15 ratio, and PETG to PLA is closer to 1:10. As I hinted previously, I believe the toolhead carriage and cover warp over time due to temperature, putting stress on the PCB. It doesn’t take much for a badly designed or poorly manufactured PCB to experience layer separation inside the board.

To try to solve this, I replaced the following components:

  • TH Board FPC Cable
  • Extruder Interface Board
  • Front Housing Assembly
  • Toolhead Middle Housing
  • Carriage Replacement :dim_button:
:dim_button: Bambu sent me this complimentary after all my other component replacements failed to fix the issue.

So, after basically rebuilding the toolhead and Bambu giving me a middle carriage for free, how does one explain that it still fails? I strongly suspect Bambu must have gathered enough data by now to know something is up—they just won’t admit it.