Ok. I was able to start a test print (spool holder light) and the printer has turned off mid print twice. I am now pretty sure that it is the power supply, as it’s led is not constantly lit either, but flashing (and very faintly at that). On a side note, I was able to consistently power on the printer (see start of this thread about how this does not work with the included power supply) from another power supply, but it’s ampere output is limited, so it is not enough to drive the motors etc.
Again, my question is: anything I can do to solidify this diagnosis or is the next step a replacement power supply?