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Re: OT (most likely) strange modem disconnection when using USB drives



Tim:
>> Anybody think of other things to try?

Frank Cox:
> That sounds to me very much like an electrical problem rather than an electronic
> problem.

'twas one of my thoughts, too.

>   Your USB enclosure device is creating a ground loop or a short that
> is causing your modem to disconnect.  Your modem is apparently the only device
> that you have that is sufficiently sensitive to be affected by this.

That thought had occurred to me, too.  I tried the nasty trick to test
that:  Plugged the USB enclosure into the mains through an adapter with
the earth pin ripped out.  Made no difference.

Isolated PC (grounded), with monitor (grounded), keyboard, mouse, USB
enclosure, no other connections.  Nothing to tie it to the any other
equipment, anywhere.  I can't see how this would cause an earth loop to
the something in the other room.

I'm not sure where you are, but in Australia, the mains power is a live
mains feed from one of the three phases in the street, with the
so-called "neutral" being a current return path to the street (anything
BUT neutral), which is grounded from place to place along the
transmission lines, and the house's earth is grounded at the house
(typically to the water pipes), and joined with the neutral at the
fusebox.

The phone lines a twisted pair of copper to the exchange, all the way,
still, as far as I'm aware.  I don't think they've updated the wiring
around here in 40 years.  Grounded at their end, but not at this end.

> Try switching the modem to a different electrical circuit and see if anything
> changes. 

Not possible, unfortunately.  Everything's on the same phase.  My only
choice, which isn't impossible, is to try running it from a battery.

> My next step, were I  you, would be to call an electrician and have him check
> things out.  Aside from the inconvenience, something like this could also be
> hazardous to your house and your life.

Also on the agenda.

-- 
(This box runs FC5, my others run FC4 & FC6, in case that's
 important to the thread.)

Don't send private replies to my address, the mailbox is ignored.
I read messages from the public lists.


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