Yesterday during a print, the printer just stopped working and all motors and fans stopped. My printer is a Graber i3.
Just before that I saw a flare coming from somewhere in the extruder or from the power supply, I couldn’t actually see.
Checked the voltage coming into the RAMPS and it was 0 V, checked voltage coming from the power supply, also 0 V. Checked the voltage coming into the power supply and it was 217 V... that’s okay, the power supply is switched to 220 V.
Today I tried further troubleshooting, by connecting the power supply to 127 V and having it switched to that voltage, before that I disconnected the RAMPS cable in case it was shorted. The result was the power supply did not work, the voltage coming from it was 0 V.
Got in contact with the manufacturer since the printer is brand new and he is sending me a new power supply, but I do want to try to find the root cause of the problem, so I started looking for shorts in the RAMPS, hotbed is okay, no continuity. Neither of the other connections have shorts, until I got to the hot end heating cartridge, in this convection I found 5 Ω resistance between phases. This was at first no surprise because it makes sense since it’s a heating element, but wanted to make sure, is it okay to have this resistance in the cartridge?
Do you guys have any other suggestion for troubleshooting or possible root causes for this issue?
UPDATE 02/OCT/2019: I decided to open the power supply, so maybe I could fix it and have it as a back up. First thing I see once opened, the fuse was blown! So I replaced it, since it is soldered and it is a 8A 250V 3x10mm, which happens to be hard to find... took quite a while. Once the repair was done, plugged it in and boom, another firework happened, this time blowing a resistor and not the fuse.
Conclusion: it wasn’t the fuse, another thing caused the first and second shortening.