Gah. Fried Power Supply - defective?

Hey all, i built a reprap mono this week, and today i was commissioning it. had a few software hiccups, but finally got through them. got all the way to the part where i was to warm the bed. i set it to 45 and off it went. the power supply made a weird noise for a moment and then *pop* a little blue flash within it and it stopped working.

now here's the deal - i DOUBLE and in some cases TRIPLE checked all of my connections/resistances, made sure it was set to 110v (i'm in the US), etc., and the power supply hadn't sounded good from the moment i turned it on. it made a rattling noise, and any time it went under even a slight load - for instance, if i moved the motors, then the noise was even worse.

i'm thinking that it was defective, but before i send it back, i want to make absolutely sure. is there anything that i should check again?

also, i believe the melzi controller is still good. i switched it back over to USB power and connected to it in pronterface just fine.

also, has anyone else run in to this?

Power supplies can do that. I've had one or two go Hiroshima on me before.

Is this a PC supply or a single output industrial supply? Either one can break. Some PC supplies need loads on outputs we do not normally use. It's *very* rare to find one that nukes when the unused output(s) are not loaded.

Back in the good old days (really old) they actually used to test things. In the late 90s I did desktop (IT) and a typical "good" failure rate for PCs was around 4%. That's when around two large bought you a shiny new 100 MHz Pentium. Laptops fared far worse, with nearly a quarter of them going belly up, at a paltry $4500 each on average. In 1998, one well known PC manufacturer who shall remain nameless (located in Nippon, they were an electronics corporation) Suffered an almost 100% failure rate, after 6 months in operation, due to defective solder. I was on a first name basis with their returns department. Their laptops, then $5000 would first stop talking to their PCMCIA busses, then just up and die all together. I mention this for two reasons, first to point out that any electronics can and will go bad from time to time.Do your due diligence, but if something is truly defective you should not be stuck with it, and second, there is an important consideration for all of us here. Those laptops went bad because the operating temperature was very close to the melting temp of the improperly mixed solder. Certainly not hot enough to have solder running down the sides of the machine like a miniaturized remake of the penultimate scene from The Hunchback of Notre Dame, but just warm enough to cause it to deform slowly over time and eventually short the IO section. In dealing with the heat within our printers, this points to the need to avoid overheating, even slightly particularly near the extruder(s).

It was the crappy OEM power supply that came with the hardware kit.

I'd spend the $45 it costs to get a good industrial 12V 30A supply and move on.

So that was it. i picked up a PC power supply, did the conversion on it, and now i'm using it for the reprap and it's working great.

that OEM power supply is a cheap piece of garbage.