kill power supply by pulling low wattage?

[sfsilicon]

I have a PC PSU set-up so that the on/off switch is permanently bridged so that the power is always on. I use the on/off switch on the back to turn the PSU and the system on and off. I'd doing this because I'm using a customer motherboard that requires a special switch for it to power on, so I have to turn on the PSU first then the motherboard.

I've had 2 power supplies die on me and a friend of mine told me that it is because the customer board I am using draws too low power 40W max on a 500W power supply. Could that be true, I'm finding it hard to believe that a PSU can die for using too little wattage. Typically PSUs die because you pull too much current (e.g. shorts). My friend said it can't be that because all PSUs have fuses.

Is there a good PSU unit that can protect itself from temporary shorts?

 

[drescherjm]

There usually is a minimum load on the 3.3V, 5V and 12V rails. Although these usually are less than 1/2 A.

Edit: At least there used to be that. I do not see any minimum load specifications on a few APFC power supplies that I looked at.

Is there a good PSU unit that can protect itself from temporary shorts?

All good power supplies do that. I mean if the current is higher than a threshold the power supply will completely shut off. Although you may be overriding that mechanism by forcing the power on.

 

[Zero82z]

I've had 2 power supplies die on me and a friend of mine told me that it is because the customer board I am using draws too low power 40W max on a 500W power supply. Could that be true

No. Putting a low load on the PSU may cause it to run out of spec, but it will not cause it to die unless the PSU is a low-quality unit to begin with. My suggestion is to get a decent quality budget unit like a 300-350W Seasonic unit, Antec Earthwatts 380W, Corsair CX430, etc., and use that. It's pretty unlikely that one of those units would fail in the application you need them for.

 

[sfsilicon]

Thanks guys!