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USB disconnects while printing!  

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SLam
 SLam
(@slam)
Eminent Member
USB disconnects while printing!

Anyone having a problem with the USB drive disconnecting and causing the print to stop?   I haven't had a sucessfull job yet, it'll start printing fine, but them I'll find the printer stopped, with the head melting away the plastic where it has stopped.  I have to re-insert the USB drive and start the job all over again.  

Posted : 17/11/2023 3:44 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: USB disconnects while printing!

have you tried a different USB memory device?

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 17/11/2023 9:24 am
GuyH
 GuyH
(@guyh)
Reputable Member
RE: USB disconnects while printing!

Many people have had this issue. It's my belief that there is a FW bug but it's caused by some slicer settings. Are you using a clean XL profile for the print or is it based on an old 3mf project/settings?

Posted : 17/11/2023 10:37 am
SLam
 SLam
(@slam)
Eminent Member
Topic starter answered:
RE:

I've tried many USB drivers, including the Prusa supplied one.  

I don't think it's gcode related, but I'm sure stranger things have happened.  There doesn't seem to be any specific gcode that causes it to disconnect, it just seems that after a certain amount of time, the USB will disconnect, and the print stops.  If I'm not watching the printer, the tool head will just sit there, still heated, and slowly melt a spot in the print.

I even checked temperatures of the display and USB drive with a thermal camera to see if it may be overheating, all temps look o.k.  The USB pins look fine as well.

I'll experience this sort of "USB disconnect / hanging" issues multiple times a print (prints usually lasting a few hours).  I haven't had a print that did not require me to pull the USB drive and pause/unpause the print to get it going again.

I'm using PrusaSlicer 2.6.1, and firmware 4.7.2.  I using the default Multi tool Prusa XL profile (Original Prusa XL - ST 0.6 nozzle), and I'm currently sticking with the default print settings, "0.25 Quality", "0.25 soluable full" and 0.25 soluable interface" profiles.  

I've found that quite a few people are having this problem.  I just noticed that this issue has been noted in the release notes for 5.1.0 alpha2 firmware. 

Has anyone found something that prevents this from happening? 

Posted : 20/11/2023 3:53 am
M.J. Caboose
(@m-j-caboose)
Trusted Member
RE: USB disconnects while printing!

I have a similar issue ... I have two theories for the problem but didn't catch up on it ... Since I have one drive where it works ... but three thumb drives giving me a random error from time to time ... From what I can tell it happens on different print states so it is very unlikely to be gCode related.

Theory 1:
The drives are quite difficult to insert ... I have the impressen the spared out hole in the plastic housing is to small or slightly missaligned to the internal connector. This causes mechanical stress which then might cause bad solder joints. When the printer is moving brief disconnections might happen ... That one easily can be fixed ... just use a rasp to enlarge the USB hole and resolder the connector on the board ... at least when you have the tools and skills to solder ...

Theory 2 (unfortunately more likeley):
The long cables cause signal integrity issues with the USB drive ... depending on how sensitive your Drive is (or how strong it's drivers are) one might work and another one might cause issues due to signaling errors. Didn't check the schematic .. but it looks like the data lines are transferred unshielded and untwisted all the way from the display board to the main PCB ... next to other digital lines like the display data. A solution would be to use propper twisted, shielded wire from the LCD board to the main board ... The implementation seems to be way out of the USB specification here.

But frankly, for a +/- 4k printer the end user shouldn't need to fix such issues. With the XL we are definetely out of the "tinkerer"-class of devices.

- Made by me -

Posted : 21/11/2023 7:57 am
Per S.
(@per-s)
Member
RE: USB disconnects while printing!

Have you tried the new Alpha-2 firmware (v5.1.0-alpha2)? For me it has been flawless, and solved several issues I had with alpha-1, among those the disconnect of the USB.

That being said, I went back to 4.7.5 after having the same problem with the alpha-1 firmware, and haven't had any USB disconnect issues since. Worth to try the new alpha-2. Not difficult to go back to 4.7.5 if you don't enjoy the alpha status.

Posted : 21/11/2023 9:56 am
Per S.
(@per-s)
Member
RE: USB disconnects while printing!

Sorry. Have you tried the beta firmware ( https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v5.1.0-beta )?

 

 

Posted : 21/11/2023 1:49 pm
SLam
 SLam
(@slam)
Eminent Member
Topic starter answered:
RE:

The USB insertion was a bit too firm for my liking, so I disassembled the front display and re-aligned things and re-assembled it so that the USB drive fits better.   

The USB traces can be unshielded, they just need to be layed out as 100 ohm differential pairs.  As "MJ Caboose" said, at this price-point, this isn't a tinker-class printer, this is dissapointing, to say the least.

If that still doesn't fix it, I'll try the alpha2 firmware as "Per S." suggested, but I'm a bit nervous doing so, since I don't want the firmware to crash if the USB drive decides to disconnect.

Is it possible to stream the gcode to the printer like the good old days with Pronterface, that would be a way to completely avoid this USB issue.

I've seen quite a few videos of uninterrupted, massive, sucessful prints.  It seems like this USB disconnection issue is rare, I haven't found many instances of this issue.   

Thanks for everyone trying to help.  I'm somewhat anoyed that my e-mail to Prusa support has gone unanswered.

Posted : 22/11/2023 3:23 am
SLam
 SLam
(@slam)
Eminent Member
Topic starter answered:
RE: USB disconnects while printing!

I just noticed there is another topic about this USB issue: 

https://forum.prusa3d.com/forum/original-prusa-xl-tool-changer-hardware-firmware-and-software-help/usb-error-mid-print/#post-685140

I'll move over to that one.  

Thanks again for the help, everyone!

Posted : 22/11/2023 3:29 am
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