Asus P3B-F problem

  • Thread starter Thread starter SM
  • Start date Start date
S

SM

Hi all,
my Asus P3B-F motherboard doesn't start at all.
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.
I read about capacitors problems but they seem to be ok (i only had a
watch!).

How can i understand why the powerGood signal is not high ?
Thanks !
 
SM said:
Hi all,
my Asus P3B-F motherboard doesn't start at all.
Click to expand...

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.
Click to expand...

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.¡
Click to expand...

[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.
Click to expand...

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
 
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 said:
SM said:
Hi all,
my Asus P3B-F motherboard doesn't start at all.
Click to expand...

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.
Click to expand...

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.¡
Click to expand...

[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.
Click to expand...

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
Click to expand...
 
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
Click to expand...

Test with the new power supply. Stop using the old power
supply. If the old power supply is about to fail, it
could damage your hardware. If the new power supply still
doesn't work, post back with the new symptoms.

Paul
 
I tested my PC with a 230W power supply and it was OK !

Thanks a lot to Paul and Stephan !!
--
SM

 
I tested my PC with a 230W power supply and it was OK !

Thanks a lot to Paul and Stephan !!
--
SM


Your P3B-F will last for a good many more years yet.
The 440BX is one solid chipset.

Enjoy,
Paul
Click to expand...
 
Thanks again,
i read about some fixes on my mb, regarding capacitors around the processor.
Do you think they are really usefull ?
I had not particular freeze situations (sometimes with Nero VE ...)

Bye
--
SM


 
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