BED Thermal Runaway + "melted" connector
I have an original MK2 that I have had just over 1 year, and it has been working pretty flawlessly for that time. I am used to having to fix minor issues, and have replaced the extruder heater core as well due to "Thermal Runaway" and a short in the original one.
Two nights ago, 11 hours into a print ( 😡 ) I had this new issue. I investigated and this is what I found, quite quickly.
Is this normal?
What is this part called so I can get a replacement?
Is there some other part I should check?
-Happy Prusa Customer
P.S. Even though I am looking for justification to buy a MK3, I would, of course, like to get this fixed and see what I can do to prevent it in the future.
Re: BED Thermal Runaway + "melted" connector
Depends if the cause is the connector being loose and overheated due to too much current or it's a symptom of the bed wires shorting or other issue. find the cause first. if the bed and it's wires checkout and the connector checks out (no short) then it might of just been loose... i would check the board too.
Re: BED Thermal Runaway + "melted" connector
I use this printer quite heavily so I do a regular check for loose cables, and I keep some spare parts for repairs that happen due to normal wear. I run this about 60 to 80 hours a week.
Does this part have a number I can search on Amazon or jameco?
Re: BED Thermal Runaway + "melted" connector
Update: found a replacement on Amazon but it seems like it's way overpriced and it won't be here for around 2 weeks. I will be scouring the local electronics shops this weekend.
Re: BED Thermal Runaway + "melted" connector
I had this exact problem this weekend myself.
Part of it was that I printed some small parts directly in the middle with the fan cooling the bed above the sensor
and the bed heating all the time at full power.
Mainly I take it those connectors always are the weak spot in those "high currency " environments.
Crap that bloody connector and solder the cables directly to the board and you will be fine until the end of days...
Re: BED Thermal Runaway + "melted" connector
There have been a number of threads started about this, i.e. https://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/heated-bed-connector-burned-crispy-o--t2414.html#p46636
It's not "normal" but does seem to be a fairly common issue, I ended up getting rid of the connector and did some soldering along with extending the wires a little, been working great ever since.
Re: BED Thermal Runaway + "melted" connector
I like the idea of the connector just in case I need to take it apart or mod it. I have had to change things a few times and having the ability to easily disconnect things is huge for me. I have ordered 3 molex branded replacements and will update the thread with my results.
Also, after finding out what the part was through some research I did find a ton of related threads about this. I'm working on a designing a replacement that is rated for higher loads that will be able to disconnect like the molex.
Re: BED Thermal Runaway + "melted" connector
As eric already mentioned, check the cable and the heated bed. Maybe it shorts somewhere. Broken cables are a common thing and you would get a same result after replacing your connector.
Find the root cause first! If you find nothing, then consider to replace the whole cable string together with a connector.
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