I have (well maybe "had") an AMD 1.1 Ghz Thunderbird.

Suddenly the PC shut off and I immediately smelled burning.When I try to
turn it on, there's no juice in the power supply (well, the fan doesn't
turn). Can I assume it's a bad PSU? If not and it's the CPU, why isn't the
PSU
fan turning?

How can you rule out a a bad motherboard? Because the case power switch
signals the
mobo, which in turn signals the PSU to power on, right? So if the mobo is
bad, then the PSU will never get the signal.

I'm trying to isolate the problem.

thanks for any help

On Sun, 18 Jul 2004 01:21:25 GMT, "Amol" <fakeemail@anon.com>
wrote:

No you can't assume it, but the odds are fair to good.

Typically that isn't how a motherboard failure works, more often
the motherboard power-on circuit works fine long after rest of
board is dead, but board is shorted out and thus the power supply
can't keep voltage levels up so it doesn't stay on, perhaps
turning back off so quickly you never even noticed it was on.

Did the burning smell a bit like popcorn? That's often a
capacitor, which might be checked on the motherboard and in the
power supply (after disconnecting it from AC for a few minutes).
Of course while you're looking around for visable damage you
might as well eye everything, including video card, etc.


Power supply can be checked by unplugging from everything but one
low-value($) drive and shorting PS-ON wire (green) to a ground
wire (black) while plugged into AC. At that point the drive and
PSU fan should be spinning.
http://69.36.189.159/usr_1034/atx_on.gif

Anything in particular that's changed in the system recently or
it's been moved or thunderstorm or ???