Power Supply Bleeding Power

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Joined
15 Oct 2009
Posts
560
Hi,

Not sure if this is the place to ask but here goes;

I have an Asus desktop PC that uses a laptop style transformer instead of a power supply.

When I first plug the power in and test it with a multimeter it shows 19v which is the rated output but within a few seconds the 19v starts decreasing down, if i leave the power plugged in then it keeps reducing down all the way to 0.7v

If I leave the plug out of the mains socket for a few minutes it goes back up to 19v.

Here's the weirdest part, if i leave the power in for a few minutes and try to power on the PC it doesn't start, sometimes the PC lights up for a second and fans try to spin but it fails and then tries again in an infinite loop. However if I leave it unplugged for a while and the moment i plug it in turn the PC on it starts and functions perfectly fine for as long as I want it.

I initially thought it was a power supply problem but I bought another power supply and this also exhibits the same behaviour. Are some power supplies meant to work like this, I am trying to work out whether i might just have been unlucky with 2 supplies or whether its a motherboard issue making the PC not start.

Thanks
 
Some power supplies require a minimum load to function correctly. If switched on with no load they may misbehave in some way. That's probably what you're seeing.
 
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