Re: P5E WS Pro - external drive drive seen on USB ports 1-6 but not 7-12.

On Mon, 27 Oct 2008 12:01:54 -0400, Paul <nospam@xxxxxxxxxx> wrote:

ChrisW wrote:
On Mon, 27 Oct 2008 12:45:49 +0000, ChrisW
<chris@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

I can only guess that it is perhaps something to do with the power
requirement of the 320Gb drive (shows up as a WDC WD32 00BEVT-22ZCT0)
and that not all USB ports are equal?

Any advice would be appreciated.

An update - I borrowed a powered USB hub and connected that into one
of the front ports. The drive was immediately recognised so it is a
power issue.

Any advice as to how to increase the power available to the front USB
ports without using a powered hub?

I was going to suggest you test with the dual USB plus Firewire
adapter cable, as a means to eliminate a bad front USB connector
on the computer case. According to the P5E WS Professional user
manual, there is one adapter assembly included in the box. You'd
be using that purely for debugging, as the Asus adapters usually
aren't a problem when it comes to signal quality. The adapter would
be an emulation of a front panel port, but with an Asus provided
connector assembly.

In the picture here, on the left, I see three 2x5 blue headers. Next
to each header, is a green rectangular Polyfuse. The Polyfuse is
usually shared by both USB ports, and has a current rating of
1 amp or more. You take the numbers printed on the Polyfuse, and
download a data*** to look up the actual current limit.

http://www.unitycorp.co.jp/asus/motherboard/intel/lga775/p5e_ws_pro/big_photo.jpg

But Polyfuses are also used near the USB stacks on the back of the
computer. You can see the green rectangles near the USB stacks.
So that part should not be different. That picture is not clear
enough, to compare component values for all five Polyfuses used
on the USB ports. I expect they're all the same. Separate Polyfuses
are usually included for PS/2 ports as well. Polyfuses are self
repairing, and the fuse closes again after it cools off and
recrystallizes.

Something else I see there, is a small six legged device near the
USB interfaces. I don't recognize what that might be. A "current
flow policeman" ? An ESD protection device ? Again, as near as
I can tell, all ports are getting the same electrical
treatment.

One thing a USB port can benefit from, like on a remote cable
assembly, is a 100uF cap to filter the +5V. That helps reduce
any transient going down the cable, when a new USB device is
plugged in. The Asus adapter cable may have one of those,
which is why testing with the Asus adapter would still be
an interesting test case.

Paul

Thanks for your suggestion. I will experiment when I get some time. I
have also tried with the Asus supplied USB ports that fit into one of
the back slots. I have tested in each of the 3 motherboard connectors
all with the same negative result. Searching the web indicates that
this is quite a common problem and all USB ports are definitely not
born equal!
.