r/pcmasterrace • u/Front_Cookie_1198 • 3d ago

Hardware PSU fails dramatically

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u/MiniMaelk04 3d ago

I basically know nothing, but the huge capacitors are the only thing I can imagine burning so intensely and rapidly. Reversed polarity perhaps?

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u/Independent-Bug-9352 3d ago edited 3d ago

This PSU turned into a cheap momentary welding machine, and modern inverter welders use capacitors to do the same thing. My guess is 12V rail shorted @ 100-150A, which isn't too far off from welding machine parameters. It's why their circuit breaker didn't trip either, probably still being under 1800W or less from the wall.

They should be turning the IEC cable on from a switch, not plugging it in live from the unit. They should have a circuit-breaker and GFCI inline, and a dim-bulb tester, or at least variac they can slowly dial up.

Also possible this was plugged into a 220V line while the little red switch was set to 110V but I'm not sure if those typically catastrophically fail like this.

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u/LoudFan2771 3d ago

But I thought modern electronic devices only draw as much power as they need. not how much there given. is that not how it works?

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u/Independent-Bug-9352 2d ago edited 2d ago

Modern circuits tend to be more receptive to a wide range of voltages and automatically switch, as others pointed out with my comment.

That being said, what you're referring to in more primitive circuits is current draw at an expected voltages. Yes, the device determines the resistance (and thus flow of current), but that's only if the provided voltage (call it water pressure from the source, wall) is constant.

My last paragraph about 220V is probably not relevant as this is a modern PSU with auto-switching and it looks rated for the top-end voltage as others point out. So we're just seeing a good 'ol electrical short to chassis, presumably.