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Subject: Re: Archos Jukebox design flaw
From: Andrew Jamieson (andrew.jamieson_at_projectlab.net)
Date: 2003-01-08


If your USB port strictly follows the spec, it is not possible to power a
standard HDD, as 500mA just doesnt cut it (these drives draw ~ 1A when
spinning up). However, many USB implementations have no, or very
rudimentary, current limiting (such as a PTC fuse). With such ports, you
can continue to draw power past the spec limit, all the way up to a level at
which either the PTC fuse trips (probably a bit over 1A, depending on the
type), or your port power supply has a cow.

So, this is one case where the Archos engineers did the right thing ....

Andrew Jamieson
----- Original Message -----
From: <for_spam_at_gmx.de>
To: <rockbox_at_cool.haxx.se>
Sent: Wednesday, January 08, 2003 11:23 AM
Subject: Archos Jukebox design flaw

> Hello,
> bought this really nice piece of hardware today at a local computerstore
for
>
> about 37?:
> http://rockbox.my-vserver.de/pics/usb20_hdd.jpg
>
> It is external usb 2.0 2.5" hdd case.
> I did a hdd upgrade for my juke some days ago and had no usage for the
> "original"
> archos hdd - so i decided to use it as additional portable storage.
> This device has additional power adapter, but i forgot to plug it in -
just
> plugged
> in the usb. And then - surprise - it worket just via usb ! no wonder -
usb
> specs say,
> that you can get 500mA from usb ports.
> This device has same Chipset (ISD300) as archos JB Recorder.
> I`m really angry, that archos development did ignore usb power !!! When
> moving
> between work and home i always have to carry 2nd device with me - the
archos
>
> power supply. grrrrrr..... (ok, now with the new device, i have an
option
> to choose..)
>
> regards
> Roland
>
>
> --
> +++ GMX - Mail, Messaging & more http://www.gmx.net +++
> NEU: Mit GMX ins Internet. Rund um die Uhr für 1 ct/ Min. surfen!
>



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