Heatbed cable cover gone melty all of a sudden  

Heatbed cable cover, well ignited into flames!!

RE: Heatbed cable cover gone melty all of a sudden

Sorry first time posting but what, and why when thing have been great, clear pliers where printed right before the second print with the black ones.  How or what do I need to do to fix, also making sure this DOESNT happen again, or to someone else's printer when they aren't home and the printer is printing. Any advice is greatly appreciated, as I love the printer and does print exceptionally well, well when it's not catching fire anyway!  

RE: Heatbed cable cover gone melty all of a sudden

open the cover and take more picture. 
It's difficult to say what's happening in the cover it could be as simple as a loose screw, or a misplaced washer, or a bad crimp on the connector

Joan

RE: Heatbed cable cover gone melty all of a sudden

I think the problem is in the area of the heating plate. Either the screws were loose or the contacts corroded, which can cause a short circuit. As Joan noted, post detailed pictures.

To be on the safe side, also measure the internal resistance of the heating plate, which should be in range of approx. 3.5 Ohm.

good luck!

Karl

RE: Heatbed cable cover gone melty all of a sudden

Yes I agree and will definitely take more pictures and post later this afternoon.  As far as the internal residence, could you be more descriptive to what dial on my multi meter, as I just wanna make sure novice when it comes to electrical.  And I am definitely investing in that smoke alarm, perfect solution thank you!!

RE:

 Here are a couple more pictures to who ever may be able to shed light on this, but I disassembled the cover, wire brushed the plastic off, seems as the terminals where and are snug, though the wire to the left looks like it is freed/melted due to the pinching/having to force the cover plate on??  Does anyone know of a remix of that particular part, this was a kit, and I followed the directions to the Tee, just trying to give all the info.  Thanks in advance for any and all suggestions! I also do have this posted in another thread I believe, I'll oppoligze ahead of time and sorry, first timer/newbie to the posting here, though have read and learned a lot through the threads, so thank you

RE: Heatbed cable cover gone melty all of a sudden

Number 2, as I don't know why I only can do 1 at a time? 

RE: Heatbed cable cover gone melty all of a sudden

And 3rd, 

RE: Heatbed cable cover gone melty all of a sudden

Good Morning Wink, 

Looking at your Pictures, it would appear that your heatbed wiring was connected incorrectly. 
 
In the image above, it would appear that the right hand connector is assembled reasonably correctly, whilst the left hand connector is assembled in the WRONG ORDER...

See the assembly guide 

https://help.prusa3d.com/guide/7-heatbed-psu-assembly_172872
Step 3

Stainless steel, is a poor conductor, and this is what has caused the localised heating... 

Additionally, it would appear that the wrong connector type has been used. Prusa specify ROUND CONNECTORS for the Heatbed end of the wires, and Fork connectors for the Einsy end of the wire

I Don't like the Prusa Wire, which is a modestly flexible wire with about 21 individual strands of copper in each wire. 
I Prefer 16AWG Flexible silicone insulated wire, which has 252 strands of copper in each wire. 
(You could use 14AWG If you wish, for extra peace of mind, (400 strands of copper wire in each wire))


make sure that you have the correct connectors for the wire ends. and that they are crimped properly

It is possible that your heatbed is damaged.  I would remove the connectors and inspect the copper connection pads on the heatbed.  
You will probably have to remove the black marks with wire wool, or fine abrasive paper. 
If all looks well, and the fibreglass has not gone flakey, 
I would smear the surface of the copper pads on the heatbed with a thin film of petroleum jelly (Vaseline) to prevent further oxidation and then re assemble the heatbed and new wire, with new screws and washers with new Locknuts, 
Making sure the connectors have the raised crimp section facing down to keep the connection low profile. 

Assuming you only have one printer, 
I would then use the printer to print a new connector cover and install the cover as soon as possible
https://www.printables.com/model/57217-i3-mk3s-printable-parts
https://www.printables.com/model/57217-i3-mk3s-printable-parts/files

Regards Joan