[Solved] Prusa MK4 missing lines randomly  

RE: Prusa MK4 missing lines randomly

I have found that this problem was resolved when i down graded to Prusa Slicer 2.6.0 and started to use the USB memory stick to transfer files to the printer. No idea why, but it works.

RE: Prusa MK4 missing lines randomly

I saw this in a recent PETG print as well, using the latest Prusaslicer and firmware.

RE:

Did you use Prusa Connect? I installed Prusa slicer 2.7.2 and have used USB for transfer in stead of Prusa Connect. I havent flashed Wifi firmware to the printer either. The problem seams to be solved.

I tried a PLA print when i had problems with the missing lines in the PETG prints, and got an extra line instead 🤣 Dont know why this is happening, but this isnt a problem any more either.

RE: Prusa MK4 missing lines randomly

Yes, I was using Prusa Connect. I may try again copying directly to the USB to see if that helps. 

RE: Prusa MK4 missing lines randomly

Disabling Prusa Connect seems to solve issue for me. Printed same gcode and same USB drive with Prusa Connect disabled and didn't have any skipped lines.

RE: Prusa MK4 missing lines randomly

Hi, 

same here. I had three prints with missing layerlines in different areas of the print. Then I disabled the Prusa Connect and the print completed successfully.

It's a shame because I was hoping to get rid of USB-Drives and SD Cards...

Thanks for sharing your workaround

RE: Prusa MK4 missing lines randomly

Have you tried the simpler Prusa Link?

PaRi

RE: Prusa MK4 missing lines randomly

No, I am using upload and then start the print at the printer manually or via Connect. This seams to work and solves the problem

RE: Prusa MK4 missing lines randomly

I wonder what makes only some printers have this problem, since most people dont encounter any problem i guess there will not be much focus on finding a solution. The Wifi functionallity was a very nice feature. 

RE: Prusa MK4 missing lines randomly

I've noticed this occasionally. I've switched to USB only, and for the last three prints I haven't had this issue again. I'd really like to use the wifi functionality though.

RE: Prusa MK4 missing lines randomly

I sometimes had the same issue via Prusa Connect.

Prusa Developers, just add hash checksum check!

RE: Prusa MK4 missing lines randomly

@Printerman Could you compare the checksum of a local gcode file and a gcode from printer? 

RE: Prusa MK4 missing lines randomly

PrusaConnect just doesn't work in my geographic location. I use prusalink instead and I have never seen the problem

RE:

I did a comparison (dos command FC) of the G-code file on the USB after transfer from Prusaslicer, and the same g-code directly from the slicer, but didnt find any difference. If i took a print that had missing lines and choose "re-print" on the printer, the next print sometimes had the missing lines and sometimes not, and in different places.

When i did a factory reset the last time, i didnt re flash/install the Wifi module, that could make a difference also perhaps.

RE: Prusa MK4 missing lines randomly

Hmm. Interesting. I know the reproducible bug with Prusa Connect \ USB.

When you try to add M600 command to bcode, the printer gets stuck if you upload it via PrusaConnect, and the printer works well if you print via USB.

Maybe guys have trouble with FS buffer, they don't run FS flush and try to read data from USB before it's physically fully written. I don't have any idea.

We can pray that the situation will be better in the next FW.

RE: Prusa MK4 missing lines randomly

Sadly I have the same issue and I don't want to disable prusa connect. I am running newest firmware, so no fix for this issue.

RE: Prusa MK4 missing lines randomly

I have this problem in FW 6.0 for MK4.   So unreliable for me I can't use any WiFi file transfer method and expect the file to be good.   A dropout or even repeated sections may occur.  Wifi Transfer from PrusaSlicer or Prusalink.  Many file transfers just fault out.  I have even replaced the WiFi card in case the memory on the WiFi card was the problem.  No change.   Monitoring via Prusa link, no problem at all.  Just WiFi file transfers.  Disconnecting my Beaglecam V2 makes no change in the behavior.   The Beaglecam WiFi file loading works well, if I want to run the printer via the Beaglecam.  Beaglecam only runs gcode, no bgcode yet.  

I have a good quality 16GB thumb drive.   Has not had formatting problems that the cheaper USB cards seem to have. 

Waiting and hoping for the next FW revision.

RE: Prusa MK4 missing lines randomly

Please write about this issue also on github.

https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/3650

RE: Prusa MK4 missing lines randomly

Ok, did that! Hope they find a solution, i really liked the WiFi funcionality!