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Ed Barton
(@ed-barton)
Active Member
Unable to calibrate

I've had my Mk3 for several years now, and had to redo the calibration.

When I do the XYZ calibration, it goes through the first stage (scanning the calibration points), but when it does the Z cal, it drops the nozzle down, pushing the heatbed down.  I then get the message "Bed leveling failed.  Sensor didn't trigger.  Debris on nozzle?"  Watching it, the light on the PINDA did turn off at the current spot.

It also was testing spot "1/9", in the back left corner (build plate all the way forward).  I noticed that it wouldn't let me move the build plate back until I ran an auto-home.  After running an auto-home, if I ran the standalone Z cal, it works fine.  However, spot "1/9" is now in the front left corner.

But that leaves me without X/Y calibration, which I can't do without including the Z calibration, which fails.

Is the XYZ calibration routine missing an auto-home step?

I'm running firmware 3.13.2-7080, hash 7aff0db6

Posted : 06/02/2024 2:46 am
Ed Barton
(@ed-barton)
Active Member
Topic starter answered:
RE: Unable to calibrate

Is there an older firmware I can roll back to?

Posted : 10/02/2024 1:38 pm
RossiRossborne
(@rossirossborne)
New Member
RE: Unable to calibrate

Similar issue here with an MK3S (updated to the last Firmware) and i can not pass the initial calibration. 

If i run "Auto Home" the PINDA-Sensor hits the first calibration point on the spot (circle on the heat bead front left). But when i run the Z calibration it misses this point by 5mm (pinda is 5mm in front of the circle). Does "Auto home" and the homing for z-calibration aim for diferent spots?

What i did:
-> Readjust and check PINDA Probe
-> Run Self Check -> All Fine
-> Run Auto Home

The documentation regarding buidling and setting it up is very good but unfortunately the errorcode i recive on this error is not really self explaning.

Posted : 10/02/2024 10:52 pm
Ed Barton
(@ed-barton)
Active Member
Topic starter answered:
RE: Unable to calibrate

For anyone else having this issue, I resolved it by rolling back to the 12.2 firmware.  I didn't test 13.0.

Posted : 16/02/2024 5:40 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Unable to calibrate

You should take this up with Prusa.  I'm running the latest firmware and life is good for me.  If there is some condition where the new firmware goes off into the weeds they'll probably want to know about it, or perhaps they know what's going on and can give you the fix.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 17/02/2024 3:49 am
Ed Barton
(@ed-barton)
Active Member
Topic starter answered:
RE: Unable to calibrate

Does Prusa not monitor their "Hardware, firmware and software help" forum besides basic moderation?

Posted : 17/02/2024 2:52 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Unable to calibrate

I wouldn't expect that.  This forum is run and managed by enthusiasts.  In a sense we're the first line of defense where we can assist with common issues encountered by new people to the hobby.  You'd be surprised how many people have issues with print bed cleanliness and getting a good z-offset.  It doesn't serve Prusa to field those issues.  Also, I don't know about you, but if I were Josef Prusa I wouldn't want to waste the time of a talented engineer by having them reading all the forums.  What a mind numbing waste of talent and a torture and a waste of money to ask an entry level employee to do it who wouldn't know what to escalate.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 17/02/2024 5:07 pm
John
 John
(@john-6)
Reputable Member
RE: Unable to calibrate

Sorry for a basic question but you have removed the build plate?

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 17/02/2024 9:20 pm
RossiRossborne
(@rossirossborne)
New Member
RE: Unable to calibrate

Yes Sir. Also i found out the spacers used by the preowner where different to the original soni swaped them to the 6mm spacers required. Cleaned all the rails and run Belt checks but still get the error: " Calibration fallen! Check the axes and rund again."

I will also check if the Firmware downgrade will help. 

Posted : 18/02/2024 7:40 pm
Eef
 Eef
(@eef)
Estimable Member
RE:

Maybe this can help: 
I have a MK2.5S.  I did not pass the z-calibration, as you described. Two issues: X-stop was displaced (no idea how, but it was 3-4mm off)
and nozzle hit the bed and same error as you described. 
Seems my (second hand printer) was upgraded a couple of times. So somehow the firmware has other measurements in memory then the reality of the printer 🙂 
It thinks the bed is about 5 mm lower then it is in reality. 
I glued a piece of LEGO on the X-stop bumper and now that is fine. 

Workaround (to make it run with latest firmware)
- Heat up nozzle and remove the nozzle. (to avoid hitting the bed)
- Place pinda about 4 mm higher (just loosen the screw a bit, untill you can push it up). 
(now the z calibration can go about 4-5mm lower then before. 
- run the calibration. 
After calibration: 
- Place PINDA back, just attach loosely (read further)
- Heat up and replace the nozzle. 
- Cool down so you do not burn your fingers 🙁 
- Place piece of paper on the bed. 
- Lower the nozzle untill the paper can/cannot be moved
- place a creditcard under the PINDA (the creditcard is about 1mm thick)
- lower the PINDA untill it hits the creditcard. Loosen screw again untill you can move it. 
- Tighten screw. Lightly is enough. 
- HOME and you can start with first layer adjustment. 

Posted : 18/02/2024 8:33 pm
RossiRossborne
(@rossirossborne)
New Member
RE: Unable to calibrate

Thank you @eef for this idea. i tested it a moment ago but it did not solve my issue 🙁

Also downgrading the firmware to 3.12.2 did not solve the issue.

Wenn running the calibration the head moves down, pinda led turns of, error occures and the pinda led is on again (without a noticable movement of the head).

Posted : 21/02/2024 10:00 pm
Eef
 Eef
(@eef)
Estimable Member
RE: Unable to calibrate

 

Posted by: @rossirossborne

Wenn running the calibration the head moves down, pinda led turns of, error occures and the pinda led is on again (without a noticable movement of the head).

Hope you already solved the issue. If not: 
- The pinda works alright. So in the procedure, it goes down, until it notices the bed and goes to next step of procedure. 
My workaround helps to make it go as low/deep as possible, so when the pinda reaches the bed, the firmware accepts it as "low enough"
Maybe give it even more room, by adjusting the pinda even a bit higher (be careful it is not higher then lowest point of extruder). 
- Next point in procedure is probably the testing if the pinda is in the middle of the circle on the bed (without plate). 
If not correct (as with my machine) you have to mechanicly change the position. For the X-direction I did that with gluing a piece of lego (with double sided tape) between switch and extruder. 
If it is correct, ai, I don't know what is next step. I guess it should start searching for the 9 magnetic points on the bed. 

Posted : 28/02/2024 6:48 am
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