New power supply, new motherboard - nothing happens!

[Viven Stanshall]

My 250W power supply burned out the other week; I left the room for
half an hour, and came back to a nasty smell and a dead pc. I fitted
a new 350W power supply, but nothing worked. I had been considering a
new motherboard and faster processor anyway, so bought both as a
bundle, with heatsink and fan. However, nothing would work, no hard
drive spin, no beeps, no psu fan. Even with nothing attached to the
board except the psu, nothing happens when I push the start button,
except the power LED coming on. I have tried a third (550W) psu just
in case the first replacement was faulty, but no dice. I have also
tried with the motherboard out of the case, to make sure it wasn't
shorting on the mountings.

Any suggestions? Should the psu fan come on with a bare motherboard
and processor, or does anything else have to be attached?

Vivien Stanshall

 

[JAD]

Even with nothing attached to the
board except the PSU, nothing happens when I push the start button,
except the power LED coming on.

Nothing will happen in that situation.



The PSU may have the voltage select switch set wrong

The CPU is not seated correctly

The video card is not seated properly

The memory has been burned/not in the proper slot

 

[Ralph Mowery]

My 250W power supply burned out the other week; I left the room for

half an hour, and came back to a nasty smell and a dead pc. I fitted
a new 350W power supply, but nothing worked. I had been considering a
new motherboard and faster processor anyway, so bought both as a
bundle, with heatsink and fan. However, nothing would work, no hard
drive spin, no beeps, no psu fan. Even with nothing attached to the
board except the psu, nothing happens when I push the start button,
except the power LED coming on. I have tried a third (550W) psu just
in case the first replacement was faulty, but no dice. I have also
tried with the motherboard out of the case, to make sure it wasn't
shorting on the mountings.

Any suggestions? Should the psu fan come on with a bare motherboard
and processor, or does anything else have to be attached?

To test an ATX power supply:

 

[dummy]

The Power Supply may require an initial load before it will boot. Try
attaching a hard drive and maybe a video card and a Floppy to boot
from.

A common problem is the motherboard shorting out to the metal part of
the case. Another problem can be Bad Memory.

Put a processor and memory on the motherboard with a video card or
integrated video and attach a monitor and see what it will do.

Sometimes a mounting post will come up in the wrong place and short
out the motherboard. You can test the motherboard on any
non-conductive surface. Just plug in the power supply and then touch
the two pins the soft on power switch goes to so the power supply will
turn on.

A new motherboard must have the CPU FAN plugged in to the right socket
on the motherboard. If you have the jumpers set wrong you may not get
any good results. Most processors are locked so they will not be
usable if you have the wrong settings. Try auto settings if possible
and use jumper free mode.

 

[ric]

To test an ATX power supply:

Hmmm...that sure looks familiar.

 

[Ralph Mowery]

Connect PS power leads to 1 or 2 IDE HDs (for a load). Jumper pin 14

Hmmm...that sure looks familiar.

Could be . If I find a good response to a problem I will save it to a file
on the hard drive and copy and past it.