Nonstandard input voltages into 100-240V PC PSUs?

[lpc32]

Can PC PSUs work equally well (ignoring efficiency) with any input voltage in their range?

[NiHaoMike]

Apart from the 100-240V AC they're rated for, most will also work with 140-380V DC.

[SeanB]

Aside from those with SCR switching of voltage range ( pretty rare these days aside from some really old designs) most will work fine anywhere in the input voltage range at full load, and often will be comfortable at part load at lower input voltages as well.

[David Hess]

If the power supply says 100 to 240 VAC, then it often has an active power factor correction input stage and should work with any AC voltage within that range.  The problem is with power supplies that use a switchable voltage doubler input stage which only works between say 90 to 140 and 180 to 280 but are marked "universal input" or 100 to 240 VAC.

Most universal input power supplies will also work with a DC input voltage which is the peak of the designed AC voltage so between 170 and 340 volts DC.

[Ian.M]

Yes, the old SMPSUs with SCR switched voltage doublers were notorious for blowing up when powered from 230V, if either there was a severe prolonged brownout, or if the input voltage detection circuit became faulty.   The usual repair (if they couldn't simply be replaced) was to rebuild them for nominally 230V only, removing the doubler switching circuit.

[lpc32]

I assumed it's either manual 115/230V selection (or fixed), or active PFC.
How common were auto-switching ones? Any specific manufactures known to be fond of them?

Though, if it's as wide as 90-140V and 180-280V, that's something too.