FLSUN Printer Issue

[Roberts_Clif]

Do you have a multi-meter?

If so could you measure the resistance across the GND symbol, N and L terminals.
This is the 3 right most terminals on the Connector Strip.

With no wires connected measures across the three terminals there should be no resistance.
It any resistance is measured between any of the 3 pins then the power supply is shorted.

I would try to power the Supply with nothing connected to the plus and minus terminals.
An only connect the L and N terminals for this test if the LED on the circuit board does not light then Controller could be bad.