Melted PSU cabel connectors,
first, I want to apologize if this topic already was opened somewhere in the Forum, but I haven’t found it yet.
My problem is melted PSU connectors of my MK2.5S as shown in the pictures enclosed.
It all started with problems heating up the bed. Sometimes the “Mintemp Bed” or “Bed Thermal Runaway” error occurred, sometimes the printer resets during the heating up process.
Therefore, I first have tested the bed thermistor and hotbed by using a multimeter, where the results (Ohm and Volt) were according the specifications
After that I checked all connections visually, where I found the melted PSU plugs.
In the Forum I found a lot of problems with melted heatbed plugs, but not with melted PSU connection.
Regarding the melted heatbed plugs there are work arounds to solder the wires directly to the Rambo, or replace the connectors, where the availability of the female part (the male part can be obtained at Prusa directly) seems not to be that easy.
My concerns regarding these solutions are, that I couldn’t found something that could have caused this melting problem, especially because it occurs directly after the PSU (the Voltage of the PSU is correct, 12V, I measured that too, and there are no visual defects at the PSU itself)
My question:
Does someone knows this problem and knows the cause of it? Is soldering the wire directly to the Rambo an appropriate (and safe) solution? …. or is it more reliable (and safe) to by some new connectors and mount them? Is it necessary to by a new Rambo and maybe a new PSU, too?
And by the way, I got the printer as MK2S kit and updated it to MK 2.5S
Thanks for your support
RE: Melted PSU cabel connectors,
the issue you have is due to poor connection between the Molex plug and socket, this has caused heat which has melted the connectors.
there was a lot of discussion in the Mk2 era. and there was much argument about Whether the connectors were up to the job. A ;pt of finger pointing and attempted blame...
the reality is,
the connectors are rated higher than the use case.
Some connectors may be worse than others,
Your environment may be more conducive to oxidation more than mine...
The wires connected to the connectors, or the connectors themselves may have been disturbed... there could be lots of contributary factors, net result ,,, it's currently broken
some folk in the past have only replaces the plug. and had a repeat failure, shortly afterwards
these plugs and sockets should always be replaced as a pair, with connectors from quality suppliers (EBAY and ali express suppliers may substitute lower quality connectors)
Prusa stock the plugs but I don't see the sockets
Zaribo can supply replacements
https://zaribo.com/electronics/41-ultimachine-rambo-mini-terminal-block-connector.html
Molex Plug Part number MOLEX 39530-0002
Molex PCB Header Socket MOLEX 39531-0002
Other suppliers include RS Components, CPC Farnell, Mouser electronics.
another option is to use different connectors, some folk have substituted XT60 connectors
Some folk have soldered the heatbed and extruder heater wires directly to the rear of the Mini rambo board
Good luck,
Joan
I am still using the connectors that were supplied when my printer, was a NEW Mk1... so the connectors can last a long time,,,,
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
RE: Melted PSU cabel connectors,
Yes, I had the same problem and posted here. Joan also helped me. I soldered the XT60 connectors and all has been fine since. Good luck!
RE: Melted PSU cabel connectors,
Joan,
thank you for your hints and your assessments.
So I'm less concerned in soldering the wires directly to the Rambo.
Thank you,
Rolf
RE: Melted PSU cabel connectors,
Bonesteel,
thank you to for the confirmation.
Regards,
Rolf