XL crashes/reboots during heater calibration  

RE: XL crashes/reboots during heater calibration

I put the machine on its side, remove the heat bed bottom cover and raise the temp. The overcurrent light comes on and the machine panics.

I think this is a software issue.

RE: XL crashes/reboots during heater calibration

You may not be wrong, or the power supplies aren't up to task, or both.  If I tell the heatbed to pre-heat to 60, it immediately reboots, says modular bed has power issue.   I was *so close to proving it was or wasn't the power supply.  Stupid power panic circuit.

Posted by: @flynny75

I put the machine on its side, remove the heat bed bottom cover and raise the temp. The overcurrent light comes on and the machine panics.

I think this is a software issue.

RE: XL crashes/reboots during heater calibration

I also have this issue. In my small sample of occurrences, I have noticed that the presence of the steel sheet makes a difference. Removing the steel sheet allows the bed to heat completely. Anyone else notice this behavior?

RE: XL crashes/reboots during heater calibration

The steel sheet made no difference in my case - pretty immediate reboot when too much of the heat bed is asked to heat too quickly (tried both with steel sheet and without).  

Posted by: @glenobie

I also have this issue. In my small sample of occurrences, I have noticed that the presence of the steel sheet makes a difference. Removing the steel sheet allows the bed to heat completely. Anyone else notice this behavior?

RE: XL crashes/reboots during heater calibration

So, I seemed to have fixed it. (Crossed fingers.)  I must have pinched one of the four colored wires going to the board during assembly. For me, it was the white one. I fully snipped the wire around where it was pinched and noticed a very tiny break. I stripped the wire back and joined the two ends back together. I ended up soldering it, but it also worked when the two ends were simply wrapped around each other. 

Those wires are very small and are made of even smaller braids, so it's pretty easy to cut one of the braids if pinched.

RE: XL crashes/reboots during heater calibration

Glad you found a fix

RE: XL crashes/reboots during heater calibration

I have checked all my wires and have no damage 🙁

I am still experiencing wierdness. If I power the cold machine on with the print sheet installed and heat it, it panics and reboots straight away. If I power off the machine, remove the sheet, and power it and heat the bed again it works. Can always repeat this when the machine is cold. Don't understand how the print sheet being installed can impact overcurrent detection, unless the magnets of the tiles are interacting with the print sheet and affecting the sensor. I might try with the heat bed PCB dangling below the tiles to try and get some distance from the magnets 

RE: XL crashes/reboots during heater calibration

I have removed the PCB from the bottom of the heated bed. I have not been able to cause this issue since. The only conclusion I can reach is that the magnetics are doing something while the print sheet is installed, and increasing the distance between the PCB and the (tiles+print sheet) 'fixes it'

• None of my wires appear to be damaged or lose
• The PCB is not damaged
• None of the tiles are damaged 
• The machine can heat properly without the print sheet
• Installing the print sheet onto a pre-heated bed eventually causes the same error
• There is no change in behaviour with paper under the print sheet to act as an electrical insulator
• The machine does not experience the error with the print sheet installed when the PCB is dangling by the wires from the tiles

Don't know what else to try until XL technical support get back to me.

RE: XL crashes/reboots during heater calibration

Well, I was wrong. Pinched wire was not my problem.  I can also confirm that the problem goes away when the PCB is not screwed into the heat bed supports. It is sounding like the PCB needs more electrical insulation from the magnets above it??

RE: XL crashes/reboots during heater calibration

I screwed the PCB back into the heat bed supports, one screw at a time. I need to do more experimenting, but right now it works if 3 of the 4 screws are in, but not  when all 4 are in.  Could a particular screw be causing a bad electrical connection? That said, it's a hard issue to test, so I'm betting that I will discover that to not really matter.

I tried making a 1mm spacer to get more distance between board and bed. That doesn't seem to have helped.

RE: XL crashes/reboots during heater calibration

Is it possible to screw theme lightly so it can move and each screw has a gap

RE:

I printed some 8.5mm spacers and reattached the PCB using M3*20 bolts. It might not be enough, will keep my eye on it. I am still waiting for Prusa Support to get back to me (waiting since 26th July)

Getting a bit fed up with this machine... Prusa touted 'next generation' electronics, and now I realise it literally cannot print from anything other than the USB. If the USB is not inserted you cannot upload gcode to it from the slicer. No wonder the wifi transfer speed is so slow, the data has to make its way from the wifi module, into the main control board, to the screen, then into the USB. Bonkers. Why not just add some flash storage to the main control board. Conversation for another topic...

RE: XL crashes/reboots during heater calibration

The PCB is already electronically isolated from the tiles and the frame by the plastic pieces that the enclosure bolts to 

Posted by: @glenobie

Well, I was wrong. Pinched wire was not my problem.  I can also confirm that the problem goes away when the PCB is not screwed into the heat bed supports. It is sounding like the PCB needs more electrical insulation from the magnets above it??

 

RE: XL crashes/reboots during heater calibration

Prusa support have directed me towards a new support page https://help.prusa3d.com/guide/how-to-fix-modular-bed-error-hw-solution_512077

I will need to request the new shielding piece. Hopefully that will sort it!

RE: XL crashes/reboots during heater calibration

I have received and fitted the new parts, the printer is now functioning properly without the need for additional standoffs or dangling the PCB by the wires 

RE: XL crashes/reboots during heater calibration

bit late to the party, im getting the same issues but i cant even boot it up the first time without it giving an error for tile 7... im wondering whats causing the issue. i noticed there has been a board revision between my XL and the work XL (mines the earlier which i bought from someone last week new in box) and my work one is a newer model with a different board on it... very strange how permanent magnets causes a board issue though  just waiting for the shield :C 

RE: XL crashes/reboots during heater calibration

Update:  After Prusa finally put the XL Sandwich on sale (meaning I could now fix my broken panic circuit for $69.90), I have replaced the sandwich,  updated the firmware, and now I'm back to the original issue - reboots or fails when doing heatbed calibration.  

Thanks to @Flynny75's post there linking to the solution which adds a metal panel, there some something else to try.  As my last experience with support was less than stellar, I just made one myself.  Took 30 minutes and used some scrap steel sheet.  Guess what?  I made it through calibration!

Time to prove wellness and then upgrade to the 5-head model.  Only took 11 months...