Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).
 
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Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).  

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AcE Krystal
(@ace-krystal)
Trusted Member
Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

I just completed building the semi-assembled Prusa XL, nice!

I turned it on, and after flashing FW 4.7.2 it started the setup-calibration process. But during the first test (Fan test) it already failed.

Physically all fan's seem to start rotating, and then speed up and stop at the end. But the screen display's some fan's have failed. I have tested multiple things, and it seems the printer is aware when a fan is blocked (by me). And it also seems to kinda randomly see different fans fails, and previous failed fans suddenly show a green check mark.

Some things I tried : 
- power cycle;
- Factory reset (soft);
- Flashing firmware 4.7.2 from USB-stick;
- Blocking fans by hand directly gives a red "x" before the test completes;
- Switched extruder 3 with extruder 1. (Extruder 3 had most problems, and this has now moved with the extruder to posistion 1. But in total all extruders seems to sometimes fail the fan test;
- Checked wiring and reseated fan plugs;
- Added more twists in the hot-end fan cable so a longer length is now twisted to potential reduce cross-talk;

None have helped so far to pass the test. My guess is that something might be wrong in the software, maybe it can't poll all 10 fan's quick enough to know every fan's status or something?

Anyone an idea what might be wrong?

Creative Engineer and 3D printing @ AcEcraft.eu

Posted : 04/11/2023 11:27 pm
AcE Krystal
(@ace-krystal)
Trusted Member
Topic starter answered:
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

After spending almost 2 hours debugging I have just brute-forces my way through the test by repeatedly re-doing the test over and over until I hit the jackpot where all fan's showed green for me and I could continue the setup process. I was planning to continue the setup process manually if I could not brute-force it. But after about 12 re-try's they all where green. In total I might have tried about 40 times in the past 2 hours.

 

I guess this is just a setup/calibration software bug, but I still would like an more official solution for the expensive printer. 🙂

Creative Engineer and 3D printing @ AcEcraft.eu

Posted : 04/11/2023 11:56 pm
1Eye liked
AcE Krystal
(@ace-krystal)
Trusted Member
Topic starter answered:
RE:

Update : I finished the rest of the calibration process. After the calibration process I did the Fan-Test yet an other number of times to see if it really was solved.
I'm still getting failed tests, but I'm also getting about 30% successful tests now. And it seems the I often fail at only one, sometimes 2 fans at the same time, instead of 3 or more that I had before.

An other potential cause idea : Too Low Fan RMP triggered by fresh Fan's?
If its a fail triggered thanks to low fan RPM, it could also be that new "out-of-the-box" fan's run a bit slower, maybe thanks to fresh applied oil/grease needing to find its place or excess needed to spin out before getting up to the RPM value's of a fan that ran already a few hours. If software RPM check was set based on a fan that had had already been running for some time, new fans might run slower during initial printer calibration. Just an idea why I see less fan's give errors the more I test.

I'm in contact with Prusa to try and figure this issue out.
I also saw someone else reporting the same thing here  (look at his 2nd bulled point: https://forum.prusa3d.com/forum/original-prusa-xl-tool-changer-hardware-firmware-and-software-help/having-a-lot-of-trouble/

Creative Engineer and 3D printing @ AcEcraft.eu

Posted : 05/11/2023 2:07 am
MileHigh3Der
(@milehigh3der)
Honorable Member
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

There is a whole thread about this. It seems like the most troublesome part is the print fan. I was getting all five failing. It seems the solution is to remove the print fan shroud, and then run the test. I got all mine to pass the first time I did that.  It seems that there might be some wisps of plastic stringing on the front fan that is causing it to fail. People have reported that cleaning up the shroud and putting it back on solves it. Perhaps you’ve run them so much now that it has done basically the same thing.

Posted : 05/11/2023 4:20 am
AcE Krystal
(@ace-krystal)
Trusted Member
Topic starter answered:
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Interesting, for me it feels about equal failure amount between part-fan and hot-end fan. I would say a bit more hot-end fans that fail. 
Where is this topic? I searched in the XL forum but did not see a topic about this yet.

I did see some trings in the part-cooling duct, but I would say they are not dragging down the fan, and blocking the airflow of these fans I though would only increase RPM on the fans. The hot-end fan might be sucking in some strings of the shielding though, and slowing it down, would need to check on that. Thanks for the tip.
Will post update if I have some news.

Creative Engineer and 3D printing @ AcEcraft.eu

Posted : 05/11/2023 9:02 pm
Tim Kukulski
(@tim-kukulski)
Member
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

My tests consistently failed with a random 3 of 5 heads passing on regular firmware. I retried after flashing the 5.0.1alpha and it passed on the first try.  (Not sure if it's a fix in the firmware or luck or whether the fans broke-in -- though my guess is that they tweaked the passing criteria.)

Posted : 14/11/2023 5:29 pm
Geoff
(@geoff)
Active Member
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

This could be it. Mine failed on one of the fans multiple times on first setup, even though both fans were running. I did notice when the test finished one of the fans stopped a bit sooner than the other. Anyway the failure didn't stop me completing the rest of the setup and printing some samples. After a total of about an hour of printing I ran the fan test again and both passed. I think you are right that a brand new fan may have a slightly stiff bearing, and perhaps the test is a bit too sensitive.

Posted : 16/11/2023 4:15 pm
1Eye
 1Eye
(@1eye)
Eminent Member
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

It took me 4-5 tries to get all 5 tools to clear the test on the same go. I was about to ping support and it finally stumbled through it and I moved on to the rest of the calibration. I wrote it off to the system shaking off the dust from shipping. My suggesting is to just keep trying.

Posted : 18/11/2023 5:40 am
Jason Miller
(@jason-miller)
Member
Fixed for me: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

I have the 2-tool XL and had the print fans failing from day one.  Went back and forth with support quite a bit (each email takes about 24 hours to get a response) and eventually was sent new fans (well, one new fan, had to wait on a second shipment a few weeks later for the second replacement).  Swapped the first replacement in and it passed the test.  When I got the second one in the mail I re-ran the tests again to confirm which one I still needed to swap out.  On that run they were BOTH failing again (firmware 5.1.0).  So I tried what MileHigh3Der said and removed the print fan shrouds - they both passed just fine then!  I can finally be rid of the annoying message before every print that I should "please calibrate"

Posted : 28/11/2023 10:13 pm
robert.e9
(@robert-e9)
New Member
RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

I had the same problem, but after reading the replies here, I thought maybe it was just a tight fan, so I ran the rest of the calibrations, which all passed, then went back to the fans, and ran them about another three or four times until they passed.

I was a bit concerned I had over tightened the screws holding the fan down, I had to remove them to put in the nuts the hold the plastic strip, because my printer had none.  But it seems that was fine ...

Posted : 17/02/2024 12:26 am
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