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Re: Losing connection with USB drives

Cross-posted to 4 groups.

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On Fri, 8/15/2025 4:50 AM, Steve Hayes wrote:
> On 9 Aug 2025 17:07:52 GMT, Frank Slootweg <this@ddress.is.invalid>
> wrote:
> 
>> Steve Hayes <hayesstw@telkomsa.net> wrote:
>>> My Windows XP computer has gradually been losing its connection with
>>> USB drives and the printer, and now seems to have lost contact
>>> altogether.
>>>
>>> Other USB devices, like mouse and keyboard work OK.
>>>
>>> For a while rebooting would make it possible to communicate with USB
>>> drives, and would cause stuck printer pages to print, but now on
>>> rebooting it shows the printer as offline, and even if I switch it to
>>> online, it does not print. 
>>>
>>> Any suggestions?
>>
>>  What does Disk Management say about the USB drives and what does
>> Device Manager (use 'Action -> Scan for hardware changes' and 'View ->
>> Show hidden devices') say about the USB drives and the (USB?) printer
>> (look at the 'Universal Serial Bus controllers' tree and the 'Disk
>> Drives' and 'Printer queues' trees)?
>>
>>  As to general USB troubleshooting, look at Uwe Sieber's USB
>> utilities at <www.uwe-sieber.de>.
> 
> Thanks very much for the advice.
> 
> I fear it may be a hardware problem, as when I booted Linux it too
> could not find any of the USN drives.
>>
>>  When responding, please crosspost to alt.windows7.general. That's of
>> course not an XP group, but several people there still use XP or also
>> use XP.
> 
> Thanks, I've done so. 

USB drives, can be operated from bus power, or from a separate power source.
Bus power is limited, and a lack of bus power causes some USB hard drives
to fail to appear when plugged in. A USB power meter, in series with
the USB connector at the host, will show whether power is present
for any period of time. A Polyfuse can open on the motherboard and
remove power from the port.

USB sticks, also draw bus power, but some of the slower bus standard USB
sticks should work even when bus power is weak. My oldest USB stick is
a 1GB one, and that is unlikely to draw a lot of power.

The power class declaration on a USB item, is unlikely to be exactly
equal to the actual power draw. For example, a device rated at "98mA",
that is a fake rating, intended to be "short of the 100mA value". The device
might draw 5mA, for some types of USB items. There have been cases, where
a 5V @ 500mA device (Alcatel Frog Modem), a power measurement showed
it was drawing 530mA. That's OK, as the Polyfuse is set to higher than that.
Only a laptop with a silicon fuse, would have trouble with an Alcatel
Frog Modem. A desktop should be fine. That device gets special mention,
because a few people did have fuse-related outages with it. Other
people were fine.

A 2.5" hard drive, some spec sheets don't show the spinup current,
but the current is on the order of 1000mA to 1100mA or so. When sitting
on the USB2 bus then, that's a wee bit of an overload. The Polyfuse
may be set at 1100mA on a "stack-of-two" with black plastic tabs.
The USB3 ports, with their 900mA rating, the shared fuse on those
is over 2 amps. Not all PCs have a USB3 port and the more-generous fuse.

In any case, it's not really a good idea, to occupy absolutely all USB
ports on the back of the computer, with USB hard drives (spinning kind).
My Seasonic supply, the label only offers "5VSB @ 2.5 amps", and
that is enough to keep five drives spinning, but it can only guarantee
that two drives spin up when power is applied. Using one or two
drives, would be as much as I would want to plug in. While at one
time, the USB ports ran off the more generous +5V rail, the ports
today run off +5VSB, and there is no jumper option to change that.
The +5VSB is a weak rail, for operating a lot of toys.

   Paul

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Thread

Losing connection with USB drives Steve Hayes <hayesstw@telkomsa.net> - 2025-08-09 18:36 +0200
  Re: Losing connection with USB drives Frank Slootweg <this@ddress.is.invalid> - 2025-08-09 17:07 +0000
    Re: Losing connection with USB drives Steve Hayes <hayesstw@telkomsa.net> - 2025-08-15 10:50 +0200
      Re: Losing connection with USB drives Paul <nospam@needed.invalid> - 2025-08-15 17:03 -0400
        Re: Losing connection with USB drives "J. P. Gilliver" <G6JPG@255soft.uk> - 2025-08-16 00:46 +0100
        Re: Losing connection with USB drives NY <me@privacy.net> - 2025-08-16 15:02 +0100
          Re: Losing connection with USB drives "J. P. Gilliver" <G6JPG@255soft.uk> - 2025-08-16 16:24 +0100
            Re: Losing connection with USB drives Steve Hayes <hayesstw@telkomsa.net> - 2025-08-16 19:36 +0200
              Re: Losing connection with USB drives "J. P. Gilliver" <G6JPG@255soft.uk> - 2025-08-16 18:45 +0100
              Re: Losing connection with USB drives NY <me@privacy.net> - 2025-08-16 21:14 +0100
              Re: Losing connection with USB drives Paul <nospam@needed.invalid> - 2025-08-16 16:50 -0400

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