Re: P4C800-E Deluxe Power Requirements

"Peter" <> wrote in message
news:...
> Does the P4C800-E Deluxe motherboard require a -5 volt power supply (in
> addition to the usual 12v)?
>
> If the answer above is Yes, what will happen (or not happen) if I use a
> power supply that does not provide -5v? Will the board work properly?
> Will other devices (drives, USB) work properly?
>
> I know -5v is not used anymore but this board *seems* to want it.
>

Why do you think it needs it? Is there a problem of some sort and you think
the lack of -5V is the problem?
Maybe it's not booting up. That can be due to incompatible RAM.
Anyhow mine runs quite happily from a power supply without -5V and Asus have
a question in their FAQ for this board that they get asked all the time.
http://support.asus.com/faq/faq.aspx...800-E%20Deluxe
Q: My newly purchased ATX power supply does not have -5V voltage. Could this
power supply be used on present motherboard?
A: ATX power supply voltage of -5V is available to traditional ISA interface
device. If your motherboard does not offer traditional ISA interface, or you
are not using any of the ISA interface device, then, your system does not
need -5V voltage.

Peter wrote:
> On Mon, 14 Apr 2008 00:48:54 +0930, "Fred" <> wrote:
>
>> "Peter" <> wrote in message
>> news:...
>>> Does the P4C800-E Deluxe motherboard require a -5 volt power supply (in
>>> addition to the usual 12v)?
>>>
>>> If the answer above is Yes, what will happen (or not happen) if I use a
>>> power supply that does not provide -5v? Will the board work properly?
>>> Will other devices (drives, USB) work properly?
>>>
>>> I know -5v is not used anymore but this board *seems* to want it.
>>>
>
>> Why do you think it needs it? Is there a problem of some sort and you think
>> the lack of -5V is the problem?
>
>
> I think the P4C-800E Deluxe board might need -5v because:
>
> 1. The manual that came with the board says it does - although it doesn't
> say what it needs it for.
>
> 2. The board has a -5v connector on it.
>
> The original power supply I had in this PC supplied -5v and everything
> worked fine. That power supplied died recently and I replaced it with a
> new one that does not have -5v. The board itself still *seems* to work OK
> (no obvious problems) but two external USB drives connected to this PC no
> longer work properly. They still work but not 100% properly and that
> started happening exactly when the -5v disappeared.
>
> So I just want to know what the real story is with -5v and this board. I
> have received totally conflicting feedback from Asus on this question. Two
> different techs replied with exact opposite answers.
>
> Peter

Describe your USB symptoms in more detail.

If you've completely lost the usage of USB ports, there is a known
problem with ICH5 and ICH5R Southbridge. There is the possibility
of latchup failure, which causes the USB ports to die at the
output pins. The logic blocks inside the chip are still
fully functional, but where the outputs drive the motherboard,
that is the point where it dies. (Looking in Device Manager,
everything looks normal, but no USB port can talk any more.)

What happens, is a lot of current flows, totem-pole style, through
the output P and N channel FETs. So much current can flow, that
in some cases, a burn mark develops on the surface of the ICH5.
For that style of failure, the motherboard will not POST ever
again. One of the enthusiast web sites, has a picture of a
burned ICH5 caused by that kind of fault.

The second kind of failure is similar to the first, except the
bond wires inside the Southbridge burn right through, before the
rest of the IC package overheats. This causes the USB ports
powered by those bond wires, to lose power. And then, the next
time you connect your external USB disk drive, there'll be
*no response*. In this case, the motherboard continues to POST,
but you won't have any USB.

So if you're not seeing any recognition at all, of any external
USB devices, you'd have to consider a "latchup failure", as an
option.

The other possibility, is the jumper on the three pin header,
that selects between +5V and +5VSB as a power source for a
USB interface, has come off. If the jumper is removed from
those pins, the USB connector will no longer have power on
the +5V pin. (USB interface pins are +5V, D+, D-, GND.)

HTH,
Paul

Peter wrote:

>
> Paul -
>
> Thanks for your reply. My USB ports still work and still provide power to
> my external USB hard drives (at least they do most of the time). The
> problem is difficult to describe. The drives have become flakey since the
> removal of the -5v power supply. When I am copying files to one of the
> external drives the first ten or so files copy normally but then the
> copying just stops. The drive no longer writes data. Also, I
> occasionally hear an audible beep coming from the drive which I think
> means a power problem.
>
> Prior to removing the -5v power supply from the PC the external drives
> worked perfectly all the time. The flakey behavior coincides exactly with
> the removal of the -5v power. When I move the external drives to a
> different PC they still work perfectly - so it's not a drive problem.
>
> This problem happens regardless of which USB port I use on the PC.
>
> Peter

Would it be possible to install a powered USB hub (has its own AC adapter),
between the P4C800-E motherboard and the external drives ?

An alternative solution, is to install a PCI USB2 card and see if the
symptoms remain. You can continue to plug your keyboard into the
motherboard USB, but could connect external enclosures to the PCI
card USB ports.

http://www.newegg.com/Product/Produc...82E16815104216

Paul

On Mon, 14 Apr 2008 00:48:54 +0930, "Fred" <> wrote:

>> Does the P4C800-E Deluxe motherboard require a -5 volt power supply (in
>> addition to the usual 12v)?
>>
>> If the answer above is Yes, what will happen (or not happen) if I use a
>> power supply that does not provide -5v? Will the board work properly?
>> Will other devices (drives, USB) work properly?
>>
>> I know -5v is not used anymore but this board *seems* to want it.
>
>
> Why do you think it needs it? Is there a problem of some sort and you think
> the lack of -5V is the problem?
> Maybe it's not booting up. That can be due to incompatible RAM.
> Anyhow mine runs quite happily from a power supply without -5V and Asus have
> a question in their FAQ for this board that they get asked all the time.
> http://support.asus.com/faq/faq.aspx...800-E%20Deluxe
> Q: My newly purchased ATX power supply does not have -5V voltage. Could this
> power supply be used on present motherboard?
> A: ATX power supply voltage of -5V is available to traditional ISA interface
> device. If your motherboard does not offer traditional ISA interface, or you
> are not using any of the ISA interface device, then, your system does not
> need -5V voltage.


I use the P4C800-E Deluxe motherboard without any -5V
and it's no problem at all. All USB ports works perfect.
This is my power supply http://www.antec.com/specs/TPII550_spe.html