New Seasonic M12II-750 EVO Just (Shorted? and) Blew Up

[FahdK]

I just finished building a system with a Seasonic M12II-750 EVO 750w PSU.

Shortly after powering on while the system was just booting up, I hear a POP, system dies and smoke coming out the top of my PC case.

The PSU seems to have blown as there was some sort of sticky liquid that sprayed out of the PSU. (Hopefully, no other components are fried, visibly ok, need to check with another PSU)

Any idea what may have caused this? Overload? But I would have had only about 200-250 watts system load. Overheat? Ambient temperature was 24C and case is well ventilated.

I'm really shocked by this and can only think of manufacturing defect. But its Seasonic and a brand new PSU at that.

Other possible causes?

 

[rgd1101]

Using the wrong voltage on the psu?

 

[FahdK]

Using the wrong voltage on the psu?

No, its a 100-240v auto switching PSU and it was also connected through a 1KV APC UPS.

 

[Xibyth]

More than likely, one of the capacitors within the unit was not properly soldered in place. These things happen even with units of high quality of reputable brands. What happens is thermal runaway, the high current combined with the short doesn't allow the capacitor to discharge, this causes heatup, which expands the chemicals inside, which then causes the cap to explode. Luckily it did not ignite, you can't put those fires out with standard extinguishers. Should that happen carefully move the unit to a paved area outside and let it burn.

For this case just clean any of it off WEARING GLOVES with isopropyl alcohol. Good news is it's a defect, also, film your build on your phone or camera and use that during the RMA process. It's particularly useful if it destroys other components.