Prusa i3 dead after heat bed use...

Hi guys, i'm fairly new to printing but have a reasonable as to how it all works. I have a prusa i3 hephestos. All has been working well until I added the heat bed, when I tried to print the extruder heated up to temp and held whilst the heat bed heated up. About half way through it just turned off and now won't turn on again. It was my understanding that the are fuses that should reset after a while but seems this isn't working, if I plug it into my laptop everything works and can access it through there, so it seems there isn't and power going through the main supply for some reason. Any ideas guys...???? thanks

Using a multimeter check your power supply and the voltages on the controller board, at the 12V input.

Well its working now, took it all apart tested the supply which works put it together and hey presto it works... Weird one.

What power supply are you using to power the heated as well? I know they come stock with a 100W supply which wouldn't be enough to add a heated so just wondering if your using an ATX and what wattage?

Power supplies usually have an automatic fuse. If it "blows" you need to unplug the power and wait a minute for it to reset.