New power supply, but still power stays on for only a second

[Kyle.Raub]

Hi all, this one has me really confused.

My PS went a few days ago (the system wouldn't turn on, period) and I
had it replaced with the exact same make and model, brand new.
Reconnecting everything, I turn it on and it almost immediately shuts
down again (after about 1.5 seconds). So I disconnected everything
but the front panel plugs and the MB and CPU power plugs (ATX). So
now the system will boot for 3-4 seconds, and then shuts down again.
As I connect the two hard drives back and the DVD/CD drive back, one
by one, turning it on each time, the length of time that the machine
runs gets shorter and shorter. I actually discovered this backwards
(unplugging them one by one and it ran longer and longer), but that's
the idea. There are no beep codes; it doesn't stay on long enough.
There is no physical indication to suspect any parts are fried, so
it's go to be something either minor in the path that's tripping the
shut down, or it is invisible-to-the-eye component damage. All of the
fans turn and the lights all come alive...for that one brief moment of
hope. I'll be searching for a spare computer to test individual
components on, but any ideas? I'm stumped.

Many thanks,
Kyle R.

 

[Kent_Diego]

Hi all, this one has me really confused.

My PS went a few days ago (the system wouldn't turn on, period) and I
had it replaced with the exact same make and model, brand new.
Reconnecting everything, I turn it on and it almost immediately shuts
down again (after about 1.5 seconds). So I disconnected everything
but the front panel plugs and the MB and CPU power plugs (ATX). So
now the system will boot for 3-4 seconds, and then shuts down again.
As I connect the two hard drives back and the DVD/CD drive back, one
by one, turning it on each time, the length of time that the machine
runs gets shorter and shorter. I actually discovered this backwards
(unplugging them one by one and it ran longer and longer), but that's
the idea. There are no beep codes; it doesn't stay on long enough.
There is no physical indication to suspect any parts are fried, so
it's go to be something either minor in the path that's tripping the
shut down, or it is invisible-to-the-eye component damage. All of the
fans turn and the lights all come alive...for that one brief moment of
hope. I'll be searching for a spare computer to test individual
components on, but any ideas? I'm stumped.

Many thanks,
Kyle R.

I had the exact same thing happen. The power supply fan seized and
eventually the PS went out. Plugging in a new PS gave the few seconds of fan
spinning you described. Further experimentation showed both the CD-ROM and
the video card were dead. It seems the motherboard was bad as well. The hard
drive and the CPU were still good. See if you can find a working system to
test your parts.

 

[SteveH]

I had the exact same thing happen. The power supply fan seized and
eventually the PS went out. Plugging in a new PS gave the few seconds
of fan spinning you described. Further experimentation showed both
the CD-ROM and the video card were dead. It seems the motherboard was
bad as well. The hard drive and the CPU were still good. See if you
can find a working system to test your parts.

It /could/ be shutting down because the mobo isn't sensing the CPU fan
spinning. Make sure the fan is plugged into the correct header on the mobo,
and if that doesn'y work, try changing the fan.