Having an issue with the connectors behind the front cover on the printhead melting due to ambient heat from the hotend building up while printing. Causing a connectivity issue with the sensors resulting in an error stating that the front cover of the printhead has fallen off when it hasn’t. When this happens, it repeatedly pauses my print before it even starts. It has also caused the Bambu Lab text to no longer light up which is what made me think to look behind the front cover in the first place. Images included below.
Doesn’t really look melted to me, highly doubt it too. You’ll run into heat creep issues waaay before those connectors melt. What your seeing is actually a glue to keep the connectors from unplugging during printing/shipping.
Maybe that last pin (white wire) in the smaller connector is not quite in all the way? Or there is some other factory defect going on. How many printing hours has it had and witch materials did you print?
Those connectors have not melted, that’s simply the silicone glue that’s used to stop them becoming detached.
The toolhead uses a hall effect sensor to detect whether the front has fallen off. If you’re looking at the head from the front, the sensor is just behind where the top left magnet seats, and indeed it uses that top left magnet to detect detachment.
The last time someone had this issue, they’d replaced/changed the hot-end and cables were applying pressure to/catching on the front of the unit causing the fault, so that would be the first thing I’d check.
Seeing as your toolhead light won’t stay lit, it may well be an issue with the connector from the PCB on the front of the toolhead, to the PCB on the back. Have a good look in that area to see if anything looks out of place. That connector also carries all of the power and signals for the hot-end and fans though so I’d expect if it was loose, you’d probably have bigger problems.
It seems that this conversation has run out of steam with no resolution. I have the same problem - the error message that the tool head front cover has fallen off and it will not go away. I’ve unseated and reseated the connectors, I’ve made sure that the magnets are all in place, I don’t see a Hall Effect sensor on top left as I face the machine but it could be hidden. I’ve logged a support ticket and got an email that it was updated but now I can’t find the ticket. Has anyone had and then resolved this issue?
I too have been seeing this message pop up now and then when the cover is still on the toolhead. Already had to restart a print several times today because of this. I’ll try and see the coming week if everything looks okay inside of it, although that is not something I really like to do.
That’s hot glue to keep the connectors from unplugging due to movement.
About the “Toolhead cover has fallen off” issue, I get that a lot too. Even if it has never fallen off. So annoying. I think my print should be close to done and I go check on the printer and it hasn’t done anything and that message is on the screen. I’ve asked about it on the sub-Reddit and I got no solutions. Out of frustration, I sometimes just pull the cover and jiggle it while putting it back on. Strangely enough, that usually fixes it for the rest of the print. But of course that’s not a real solution.
