--- In nslu2-general%40yahoogroups.com">nslu2-general
yahoogroups.com, "Mike (mwester)" <mwester...>
wrote:
>
> docbillnet wrote:
> This is a surprising result.
>
> Can you provide some additional detail on how you determined this?
A lot of speculation, and very little evidence. Call it an educated
guess, not an experimentally determined fact. The only experimentally
determined fact in this case us using a powered hub speeds up my USB
ports by a factor of 6. It is an assumption that this is because of a
voltage drop in the NSLU2.
I will try and find my multimeter and verify my guess. If the second
unit produces the same results, I should be able to measure voltage
prior to cutting the resistor. I see on the wiki someone already
measured voltages in their unit with and without the resister, and
came up with a 0.1 V difference. If I see the same 0.1 V drop, then I
would also need to have a bad power supply, as typically you have to
drop the voltage above 4.7V is sufficient for USB 2.0.
> is the voltage on the bus with the resistor, vs without? What other
> devices are plugged into the NSLU2 (the +5V on the USB ports are all
> directly wired together to the main +5V within the device, i.e.
there is
> no isolation between ports themselves, or ports and the device itself)?
>
> Can you also check to see that your power supply is adequate? (There
> seems to be an unusually high number of reports of defective power
> supplies being shipped -- either that or we've just managed to track
> more problems down to this root cause lately.)
Possibly. Typically, I find there is a higher chance of getting a
defective part in a refurbished unit. Typically they don't know why
the original owner returned it, so if the problem does not show up in
there tests, the item will be resold without fixing the actual problem.
Bill
.
