P5AD2-E Premium - no power on

[Guest]

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

I just got a new P5AD2-E motherboard. It was working fine until this
moring, when I found the machine off (I left it running a import, while
having breakfast). When I pressed the power button, I hear a noise and
could smell the typical smell of an electical component buring - I
switched it off, but of course since then it is dead. The power
indicator LED SB_PWR1 is lit (indicating that the power supply is OK,
but when I press the power button I hear a short hissing noise and then
all is dead.

This machine is going to be my HTPC and thus I have changed the
standard CPU cooler for a passive one (Silverstone NT01v2.0).

My theory is that the process I was running, demanded a lot of CPU, the
board reacted by stepping up the clock (the AI NOS function) and my
processor got very hot and of course pulled a lot of power from the
board. One of the power components took a beeting and the machine
powered off due to that or the high processor temp. When I switched
the machine back on, a power component popped. - I smelled the board
and the smell is strongest just right of the processor where there are
4 power components - one of them is standing up - I think this guy
could not handle the load.

I have tried a lot of different things to get the board going or to at
least get something out of it, but nothing.

Has any of you seen something similar and do you have any comments to
my theory?
Do you think my processor is OK?


--
jacofourie

 

[Paul]

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <jacofourie.1qucjq@news.computerbanter.com>, jacofourie
<jacofourie.1qucjq@news.computerbanter.com> wrote:

> I just got a new P5AD2-E motherboard. It was working fine until
> thismoring, when I found the machine off (I left it running a import,
> whilehaving breakfast). When I pressed the power button, I hear a
> noise andcould smell the typical smell of an electical component
> buring - Iswitched it off, but of course since then it is dead.
> The powerindicator LED SB_PWR1 is lit (indicating that the power
> supply is OK,but when I press the power button I hear a short
> hissing noise and thenall is dead.
>
> This machine is going to be my HTPC and thus I have changed
> thestandard CPU cooler for a passive one (Silverstone NT01v2.0).
>
> My theory is that the process I was running, demanded a lot of
> CPU, theboard reacted by stepping up the clock (the AI NOS function)
> and myprocessor got very hot and of course pulled a lot of power
> from theboard. One of the power components took a beeting and the
> machinepowered off due to that or the high processor temp. When I
> switchedthe machine back on, a power component popped. - I smelled
> the boardand the smell is strongest just right of the processor
> where there are4 power components - one of them is standing up -
> I think this guycould not handle the load.
>
> I have tried a lot of different things to get the board going or
> to atleast get something out of it, but nothing.
>
> Has any of you seen something similar and do you have any comments
> tomy theory?
> Do you think my processor is OK?-- jacofourie

One thing that the Silverstone design does not provide, is any
moving air over the Vcore MOSFETs. I expect what has happened,
is the MOSFETs went into thermal runaway, or a capacitor has
failed. You'll need to RMA the board under warranty.

I have a picture of a P5AD2-E motherboard, but the resolution isn't
too good. It looks like the Vcore regulator could be an ADP3180.
That device has crowbar protection on overvoltage, so the Vcore
circuit may have sacrificed itself, in order to protect your
processor. There is a good chance the processor is still good.

When you get your repaired motherboard back in about three
weeks or so, I would suggest the following test. Install the
motherboard, install the Silverstone cooler (including the
two fans that bolt to it). Boot the OS. Download a copy of
Prime95 (mersenne.org). Open the side of the PC. Start
Prime95 running. Immediately hold the chassis with one hand
(to drain any static charge off your body), then take a finger
of the other hand, and touch the components in the vicinity of
the Vcore circuit. Also, take a look for the other MOSFETs on the
motherboard (black square with three leads sticking out one end).
If you cannot hold a finger on any of these for more than 2 seconds
without getting burned, that component is running at about 50-55C.
Now quit Prime95, and make some notes of what parts of the motherboard
got hot.

On my P4C800-E, I've found two MOSFETs in the DIMM power circuit
get hot (measured at 40C). I haven't taken any additional precautions
with them, as that is only about 15C over ambient. While it is possible
to rig up heatsinks for MOSFETs, the best installation method is
also the most difficult to do - there are some sinks that you solder
to the tab of the MOSFET, and something like that should be done
at the factory. Just sticking a heatsink to the plastic body of
the MOSFET, won't help very much (it may make you feel better, but
not make the MOSFET any cooler).

If you find the components around the processor are getting hot, then
mount a 120mm fan above the center of the processor. Make the fan
blow down onto the board, and use a rheobus or Zalman Fanmate2 to
control the rotation rate of the fan. Some moving air should be
enough to keep the circuit properly cooled.

Also, with your unique cooling method, you should use your favorite
search engine, to find pictures of the insides of a Shuttle PC. See
how they cool the Vcore circuitry. If I see any unique ideas there,
I'll post back later today. That Silverstone cooler looks like a
good concept, but when you make radical changes to some of the
assumptions about how the air moves in a PC, you have to be
prepared for unexpected side effects. Taking the temperature of the
motherboard components with your finger, is a quick way to find
those kinds of problems.

I think the record for hot components on an Asus motherboard, was
one of the first A7N8X boards. Someone took a picture with a
thermal imager, and found a tiny eight pin chip on the motherboard
running at 99C. That chip was one of the first things I checked,
when I bought my A7N8X-E Deluxe

Paul

 

[Paul]

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <nospam-1806051904330001@192.168.1.178>, nospam@needed.com
(Paul) wrote:

> Also, with your unique cooling method, you should use your favorite
> search engine, to find pictures of the insides of a Shuttle PC. See
> how they cool the Vcore circuitry. If I see any unique ideas there,
> I'll post back later today.
>
> Paul

I looked at a few Shuttle reviews, and some of the earlier
Shuttle designs had terrible treatment of the Vcore circuit.
One design placed the power supply body over top of the
Vcore circuit, so there was next to no air movement in
that area. A more recent design, using an Intel 915P
chipset, had an excellent design, where the heatpipe-nased
heatsink and fan, form a "wind tunnel" from one side of the
Shuttle case to the other. The Vcore circuit in that case,
is contained inside the wind tunnel, so the Vcore gets
excellent cooling. You might want to make a shroud leading from the
fans on your Silverstone cooler, back towards the CPU socket,
so that the Vcore circuit gets some air movement around it.

Paul