Strange power supply problem

Archived from groups: comp.sys.laptops (More info?)

I have a Compaq Presario 700US notebook that wont even POST when plugged
into AC or battery - no sounds, no lights, nothing. I noticed that when I
plug powersupply into the laptop the light on the powersupply turns off (the
light on the powersupply does come on fine when it isn't plugged into the
laptop). I have checked the voltage coming in from the battery and the
powersupply and that doesnt appear to be the problem. I have taking the
notebook apart and other then verifying the power coming in, there isnt much
else I can test.

Could this be a motherboard gone bad? Any suggestions?

Archived from groups: comp.sys.laptops (More info?)

Lewin A.R.W. Edwards wrote:
>>into AC or battery - no sounds, no lights, nothing. I noticed that when I
>>plug powersupply into the laptop the light on the powersupply turns off (the
>
>
> This suggests an overcurrent condition, probably a dead short in the
> laptop, which is forcing the brick into shutdown. You can try to
> isolate this step by step by lifting components off the board to
> locate the short.

Have you tried connecting the power supply to the laptop while the
battery is removed ? If you already have, sorry for asking the obvious
but if you have not, chances are the battery is causing the problem.
Well, I hope, since the alternative is indeed the motherboard and on a
laptop, there is not much you can remove to isolate the problem ...

Regards

--
John Doue

Archived from groups: comp.sys.laptops (More info?)

I agree. Sounds like a dead short in the systemboard. You could unplug
the components (the power boards) from the systemboard but I don't think
so.