Ramps 1.4 power connector melted
Last night I was getting ready for a new print when I smelled something out of the usual, it came from the ramps power connector adapter, both negative terminals where melted, my cables are rated for the current, the only major change was changing to marlin from sprinter, all I can think of is poor contact between the adapter and the plug itself
No damage to the cables or to the ramps board was made
Any ideas?
Thanks
Simon
Bad quality connector that had too much resistance (presumably more than specced) so heated up too much. That or your ramps is usi g an under specced connector.
Other solution will be to connect directly to the power connector without the adapter, with more robust connectors but my doubt is in the sprinter to marlin change that could have triggered this
I’ve ran into a similar issue. On mine, the strain on the connector caused the removable connector to become loose and probably started sparking. Eventually the connector is covered with soot and no longer make good contact. Mine did not melt so bad so it was an occasional drop on the heat elements. I was going to replace the connector pair, but I discovered that the OTHER screw terminals that is on the ramps board also contains the same pins that I needed so I supply the power via those instead of the removable plug. Of course now all the cables are secured onto a wooden base so this should not happen again. Good luck!
Firmwares generally have a setting to limit the maximum duty cycle to the bed - that might have been set to a sane value in Sprinter, but not in Marlin.
But yeah, i’ve had that type of connector melt down on me, too. I now use five 2,54mm pin headers + connectors (the standard arduino-stlye female connector) for each of the bed wires and have never had an issue with those.
@Thomas_Sanladerer these were the power wires, rather than heater wires, though, at least it sounds like it.
Thanks guys, I’ll check on duty cycle for marlin and change the connector type
Just to clarify, the connector shown above is for the power to the ramps not the heated bed.
What’s your power supply? And was this connected to a USB cable at the time? Apart from arcing as discussed above, the only other thing that makes sense is a current loop formed through the PSU to the ground of the USB cable. This also depends on the power supply of the USB device on the other end (eg: desktop/laptop).
Yes, the usb has been always connected to a netbook during prints, I’ll check if there’s a current loop, thanks for the idea
I got the same - and re-soldered 4 fires and place another connector (direct connection to power supply), then power supply died - new one instead of 250Wt is 350Wt, now it is working fine on Prusa Mendel - under temperature in room of 23C, after 6 hours printing (I print PVA molds) fires defiantly hot.
