Hi all! Long time Mendelmax user here. Having my first major problem in several years (which is at least some good news!)

Yesterday, I was attempting a few prints to recalibrate (been a few months since the last time I used the printer) and things were going well. I started smelling a faint electronic burning smell, however, and stopped printing to examine.

I couldn't see any obvious issues, so I tried some prints again today. While my printer was preheating using the Marlin preheat function, the electronic burning smell came back and got stronger, after which the printer shut off.

I looked around the printer, and to my surprise the back of my power supply was badly burned! (See attached picture).

I'm not exactly sure what caused this. The only other symptom I've experienced is that over a long period of time (in the span of the last few years that I've had the printer) the heated bed was seemingly becoming more and more difficult to heat; over time it would be harder to get to 105, then to 100, then recently it seemed I could only get the bed up to about 95 degrees.

I'm just trying to get a head check here; I've already ordered a replacement power supply. Is it simply that the power supply went bad? Are there other likely causes or things I should check to make sure the printer is safe before I re-plug it in after I replace the power supply? Thanks so much in advance for any guidance here!

It looks to me that your V+ connection screw was probably loose, or the crimp was bad.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

That very well may have been, dc42. Thanks for the heads up. If I just replace the power supply, do you think it will be OK? I'll do a really solid inspection of everything else to be sure, but just trying to make sure I don't do anything too dangerous.

You may not need to replace the power supply. Have you tried replacing the burned wire and using one of the other V+ output terminals?

Edited 1 time(s). Last edit at 04/20/2016 02:22AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].