Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
Thanks again Stephan,
i think i will test a new PSU today or tomorrow.
In a while i downloaded the ATX PS guide and i will study it.
Two questions:
- when i checked pin 14 P_ON i detected 0V, is ir right ?
- was it normal that when i inserted the power cord i see the PC powered on
for a second and then it powered off ?
Thanks
--
SM
"Stephan Grossklass" <sgrokla-nospam04q2@yahoo.de> ha scritto nel messaggio
news:d3jqna$h5j$05$1@news.t-online.com...
> SM schrieb:
>
> > Hi all,
> > my Asus P3B-F motherboard doesn't start at all.
>
> So, did you try another PSU now?
>
> > When i plug the power cord i see the internal LED green.
> > I checked all the ATX power supply connector pins: all the voltages are
> > present but the PowerGood signal is low.
>
> From the ATX power supply design guide v2.01, as found on
> formfactors.org:
>
> > 3.3.1. PWR_OK
> > PWR_OK is a ´power good¡ signal. It should be asserted high by the power
supply to
> > indicate that the +12 VDC, +5VDC, and +3.3VDC outputs are above the
under-voltage
> > thresholds listed in Section 3.2.1 and that sufficient mains energy is
stored by the converter
> > to guarantee continuous power operation within specification for at
least the duration
> > specified in Section 3.2.11, ´Voltage Hold-up Time.¡
>
> [That's 17 ms.]
>
> > Conversely, PWR_OK should be deasserted
> > to a low state when any of the +12 VDC, +5 VDC, or +3.3 VDC output
voltages
> > falls below its under-voltage threshold, or when mains power has been
removed for a time
> > sufficiently long such that power supply operation cannot be guaranteed
beyond the powerdown
> > warning time.
>
> So since you apparently managed to turn on the PSU but PWR_OK is low
> nonetheless (which in turn tells the board that it better not power up),
> I'd say that the power supply is defective. (If it's as old as the board
> or older, it may simply have dried-out caps. But given that you can buy
> good, solid PSUs like the Fortron Source FSP300-60PN for not too much
> money, a repair is hardly worth it.)
>
> Stephan
> --
> Home: http://stephan.win31.de/
> PC#6: i440BX, 2xP3-500E, 704 MiB, 18+80 GB, R9k AGP 64 MiB, 110W