So a question. I have a Printrbot Simple Metal with heated bed and randomly

So a question. I have a Printrbot Simple Metal with heated bed and randomly my ATX power supply will just not switch on. Normally if I leave it for maybe an hour or so, it, or the Printrbot seems to “reset” itself and I’m good to go again. Tonight it just wouldn’t “reset”. I had to disconnect it from the Printrbot before it would switch on again? Any idea what’s happening here.

What’s happening is that there is a “polyfuse” in your power supply. When too much current is pulled through it, it heats up, and increases resistance substantially. This shuts the power supply off. As this happens more and more, the polyfuse becomes easier and easier to trip.

You’re probably going to need a replacement power supply. Additionally, see if it happens when something like the heated bed is off.

I’ve had some reports of a short in the heated bed- the traces touching the metal bed. We switched Pcb design and manufacturer to fix the possibility. Some older green beds may fall prey to this. A piece of tape over the traces solves it. It could be causing the short occasionally.

So there’s definitely a short then? :confused: I thought it just may be the Printrbot switching off for whatever reason. The PSU is brand new. I installed it with the heated bed maybe a month ago. Brook if memory serves, I think the element is red, I can’t remember it being green? It was a kit. I’ll need to strip it down then and see what’s happening.

Ok- if it’s red, we have not had any issues with that bed shorting. Btw, all green beds installed on our printers are now protected from the short with a kapton insulator.

If the psu is browning out, it could be a short- if some hot wire grounds out, it just shuts down. Check the heatbed and the hotend wires.