Firmware 7.1.0 S5 printer unrealistic height difference - won't level bed

[FishGuy 1]

We upgraded firmware on our S5 about a week ago. Since then we have not been able to autolevel the bed. Here is what we have done.

 

Manual level

clean bed

swap bed

swap filament

reset springs to two turns from tight

manual level

swap printheads - tried three sizes in left and two in right. Both AA and BB in right

upgraded firmware again

check capacitive sensor for noise (values ranged from 2.2 - 5.2 over 10 readings in three days)

change silicone heat shield

check sensor wires

check plugs to head board

 

We are all out of ideas. There has been a thread asking to check a log file for 'unrealistic difference' but we can't find that in the logs we have dumped. Does anyone have any ideas we have not tried? 

 

[FishGuy 1]

An addendum to the things we have tried. We backed up to 7.0.3 firmware. The error persists. So it is not firmware related. Also, we have power cycled the machine, including leaving it off overnight.

[Carla_Birch 116]

Your manual bed level could be to tight what makes the bed lower than should be, @fbrc8-erin i think would likely know what the gap should be between the metal frame and the headed bed.

 

Also have you reseated all the plugs in the printhead?

[MariMakes 199]

Hey @FishGuy

Ugh, I'm sorry to hear that you are stuck.

That's a super extensive troubleshooting list. 

 

The things I would still check is the state of the data cable from the printhead going to the motherboard.
Is it clicked in snuggly? Is it damaged? 
Something I easily overlook myself is the Lift switch calibration. Is it being performed correclty?

The capacitive sensor might be affected to other things in the room. Is there heavy machinery nearby? Or is the room exposed to any other vibrations? 

If this doesn't help you can try to consult this support page. 

https://support.ultimaker.com/hc/en-us/articles/360013133699-Active-leveling-errors
The last step on this troubleshooting website is to submit a ticket to the Ultimaker support specialists.

Good luck! 🤞

[FishGuy 1]

Thanks MariMakes,

 

I checked the cable. It is snug. I plugged and unplugged it in case there was something caught. The capacitive sensor test is giving numbers below 5, so I do not think noise is an issue. 

 

I need some prints, so I have resorted to Ultitune to turn off bed leveling. Not ideal, but I need this to work over the weekend. i will try reaching out to customer service. 

 

Adam

[FishGuy 1]

I believe we have resolved this issue. There is a small spring above the second nozzle. That spring had twisted down a few turns through the hole. This reduced the downforce on the second nozzle when it was swapped.  

[SanneM 12]

Hi @FishGuy!

 

That is a very interesting failure mode, do you still have the logs from when this failed?

Those would be interesting for analysis, perhaps the algorithm can be tuned do detect this case more specifically