Nearly a Fire, No Confidence, What next?
Had some issues with unexpected resets a week ago, so I explored and found that the connection from the power supply to the miniRAMBo Board on my mk2.5s were worn from age. I replaced the connectors with the green ones shown. Did one print yesterday with no issues, but this morning I preheated to swap filament and smelled smoke. Quickly powered off and disconnected. Upon inspection found that the new connector was burned as shown. I'm resistant to do anything else with this printer. Any recommendations on how to proceed?
Thanks, Jon
Check the fuses, if none are blown then this is most likely a faulty plug/socket.
For peace of mind, install a smoke alarm above the printer.
Cheerio,
RE: Nearly a Fire, No Confidence, What next?
I can solder a connection directly to the rear of the board for both these power inputs assuming it is a connector issue. I did this for the bed power supply.
Question is - will this really resolve the issue or is it likely an issue with the board that will still exist after I bypass the socket/connector?
JB
If you have the right fuses you shouldn't be able to draw enough power for really rapid ignition so a smoke detector ought to be enough warning.
...and I don't recall ever hearing of a Prusa Printer derived fire although a certain brand with an inflammable acrylic frame caused a few about ten years ago.
Cheerio,
RE: Nearly a Fire, No Confidence, What next?
Well, it was smoking significantly, and where there's smoke...
The proper fuses were installed.
"Cheerio" was not what I was thinking.
Well, it was smoking significantly, and where there's smoke...
.. it can be detected.
And the detector can alarm, trigger an automatic fire extinguisher and trip the power. Trip just the local supply, not the mains as you don't want to be groping in the dark if a fire starts elsewhere in the house.
Cheerio,
RE: Nearly a Fire, No Confidence, What next?
Would be curious if anyone has any constructive advice here. TIA
RE: Nearly a Fire, No Confidence, What next?
There are different quality connectors
Good quality connectors properly seated should be fine. My mini Rambo is still good since 2015. I think they are rated at 20 amps
Some people solder direct to the PCB.
Others use a 60 amp connector to make the connection removable
Yet another approach is to use an external MOSFET switch. And use the signal off the mini Rambo to control the power
Joan
Regards Joan
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: Nearly a Fire, No Confidence, What next?
If the connector runs that hot, there must be a bad contact which causes a higher-than-normal resistance, and hence resistive heating right at the plug.
It could be the plug-to-socket connection itself. I take it you only replaced the plug, not the socket on the PCB? Check the socket contacts -- are they oxidized on the surface, or are they loose, not clamping the plug contacts tightly?
Or it could be your new connection between the plug and the wire. Is that a crimped connection? Did you crimp it properly?
I would redo the connection with a new plug and socket, and measure the resistance from the power supply to the miniRambo PCB. (Multimeter in Ohm mode, printer power off, of course.)
RE: Nearly a Fire, No Confidence, What next?
Thank you both, the other parts of the connection do appear fine. I will also check the resistance levels, but am leaning towards soldering to the board directly with 60A connectors.
RE: Nearly a Fire, No Confidence, What next?
A follow up - I did solder 60A connectors wired directly to the board with the other ends on the power supply. All works fine.