can't dtermine the problem

[kaspr79]

i have an asus p3b-f mother board, had an old 250 watt power supply
recently bought a new case with a 400 watt supply, when i connect th
power switch to the panel and everything else is connected properl
nothing starts up. can't tell if its a power switch problem, if m
mother board is toast or if the power supply is too strong...will th
power supply run if its too strong

 

[DaveW]

There is no such thing as too strong of a PSU. The system will only use the
amount of power it needs.

 

[kony]

i have an asus p3b-f mother board, had an old 250 watt power supply,
recently bought a new case with a 400 watt supply, when i connect the
power switch to the panel and everything else is connected properly
nothing starts up. can't tell if its a power switch problem, if my
mother board is toast or if the power supply is too strong...will the
power supply run if its too strong?

Check to be sure (that if the PSU has a...) the AC voltage
switch on the back is set correct per your location.

Do you still have the old PSU? You might try it.
Has this new PSU been shown working with any other board?
If you have a multimeter you might take voltage readings.

You might check to be sure this new case doesn't have any
board standoffs in the wrong places, potentially shorting
out the back of the board.

Having a PSU with a higher wattage rating than you need is
not a problem, will not cause this except in very rare cases
where there was a very high 12V amperage and no load on the
12V rail. Having a hard drive or two and some fans is
enough of a 12V load that it shouldn't be an issue.

To rule out the power switch, disconnect all the case front
panel wiring. Turn on the system by momentarily shorting
together the mobo's two power-on pins with a metallic object
(carefully).

You can also do a crude PSU test by unplugging the PSU from
ALL parts except one old hard drive, then use a paperclip or
similar to short pin 14 (usually green wire), the PS-On pin
to ground (an adjacent black wire most often).
http://69.36.189.159/usr_1034/atx_on.gif

 

[philo]

i have an asus p3b-f mother board, had an old 250 watt power supply,
recently bought a new case with a 400 watt supply, when i connect the
power switch to the panel and everything else is connected properly
nothing starts up. can't tell if its a power switch problem, if my
mother board is toast or if the power supply is too strong...will the
power supply run if its too strong?

disconnect all but the essentials
and give it a try.

it my be something simple such as the floppy drive power cable plugged in
wrong

 

[Jester]

Most new motherboards have a 20 or 24 pin power connector. They also
may ahave a 4 pin 12v power connector. If the MB has a 4 pin make sure
the power supply is plugged in.