Urgent help needed: cannot switch off PC

[Terry Pinnell]

I installed a 4-socket self-powered USB hub today on my XP Home PC. My
various USB devices seemed to work OK (with exception of the new one,
a QX3 microscope, that had prompted the purchase, but that's a
separate issue). Here's a picture of it:
http://www.terrypin.dial.pipex.com/Images/USBHub.jpg

But, on switching off my PC, which seemed to power down as usual, the
amber and green power lights on the Mesh Athlon 1800 didn't go out.
And the PC wouldn't then respond to being switched on again. Nor did
Reset have any effect. Nor holding the power button depressed. Serious
worry and seems to defy logic.

The power lights would go out if I removed either the DC power to the
hub, or the USB lead connecting it to the PC. But even then the PC
wouldn't start up again. Removing and replacing mains plug, or on/off
button at rear of PC had no effect either

Somehow, after fiddling around, cursing a bit, it DID then respond.
But naturally I am now very nervous about switching it off. Using
Start>Turn Off Computer>Restart works OK - it's just the full Turn Off
that doesn't.

There's nothing to help in the single page 'User Manual' (headed USB
1.1 Hub GUH-01 GUH-02, with no contact or web info.

Can anyone offer any help please?

 

[Rob]

I installed a 4-socket self-powered USB hub today on my XP Home PC. My
various USB devices seemed to work OK (with exception of the new one,
a QX3 microscope, that had prompted the purchase, but that's a
separate issue). Here's a picture of it:
http://www.terrypin.dial.pipex.com/Images/USBHub.jpg

But, on switching off my PC, which seemed to power down as usual, the
amber and green power lights on the Mesh Athlon 1800 didn't go out.
And the PC wouldn't then respond to being switched on again. Nor did
Reset have any effect. Nor holding the power button depressed. Serious
worry and seems to defy logic.

The power lights would go out if I removed either the DC power to the
hub, or the USB lead connecting it to the PC. But even then the PC
wouldn't start up again. Removing and replacing mains plug, or on/off
button at rear of PC had no effect either

Somehow, after fiddling around, cursing a bit, it DID then respond.
But naturally I am now very nervous about switching it off. Using
Start>Turn Off Computer>Restart works OK - it's just the full Turn Off
that doesn't.

There's nothing to help in the single page 'User Manual' (headed USB
1.1 Hub GUH-01 GUH-02, with no contact or web info.

Can anyone offer any help please?

I don't have an answer but here's some web info that might help.
http://www.canyon-tech.com/net/index/E4E3C503-2550-715F-1DF66E1EC86B8D2C
Ther is some contact info there.

Rob

 

[Paul]

I installed a 4-socket self-powered USB hub today on my XP Home PC. My
various USB devices seemed to work OK (with exception of the new one,
a QX3 microscope, that had prompted the purchase, but that's a
separate issue). Here's a picture of it:
http://www.terrypin.dial.pipex.com/Images/USBHub.jpg

But, on switching off my PC, which seemed to power down as usual, the
amber and green power lights on the Mesh Athlon 1800 didn't go out.
And the PC wouldn't then respond to being switched on again. Nor did
Reset have any effect. Nor holding the power button depressed. Serious
worry and seems to defy logic.

The power lights would go out if I removed either the DC power to the
hub, or the USB lead connecting it to the PC. But even then the PC
wouldn't start up again. Removing and replacing mains plug, or on/off
button at rear of PC had no effect either

Somehow, after fiddling around, cursing a bit, it DID then respond.
But naturally I am now very nervous about switching it off. Using
Start>Turn Off Computer>Restart works OK - it's just the full Turn Off
that doesn't.

There's nothing to help in the single page 'User Manual' (headed USB
1.1 Hub GUH-01 GUH-02, with no contact or web info.

Can anyone offer any help please?

Terry, West Sussex, UK

It sounds like the +5V on the self powered hub is flowing backwards
into the computer, and keeping the +5V charged. All devices that source
power into a shared power bus, should use a Schottky diode in series
with their power "contribution", to keep this sort of thing from
happening. I don't know how you can fix this as an end user.


+5V +5V
| |
____ ----
\/ \/
-- --
| Cable |
|_____________________________|

You would think there would be one port on the hub, intended for
connection to the host, that wouldn't be self powered (i.e. attempting
to source power).

HTH,
Paul

 

[Terry Pinnell]

I don't have an answer but here's some web info that might help.
http://www.canyon-tech.com/net/index/E4E3C503-2550-715F-1DF66E1EC86B8D2C
Ther is some contact info there.

Thanks, Rob, that's helpful. I've rattled off an email to the contact
address I found there.

Meanwhile, it consistently happens only when the USB hub is powered.
After removing the DC supply plug from the USB hub, I can switch off
the PC fully as normal.

In fact, that's what I'm going to do for the time being, because I
can't get the device (for which I bought the powered hub) to work
anyway. It's a 'Digital Blue QX3 Computer Microscope', and, after
installing software and drivers from its CD, refuses to communicate
with my XP PC ;-[

 

[Rob]

I don't have an answer but here's some web info that might help.
http://www.canyon-tech.com/net/index/E4E3C503-2550-715F-1DF66E1EC86B8D2C
Ther is some contact info there.

Thanks, Rob, that's helpful. I've rattled off an email to the contact
address I found there.

Meanwhile, it consistently happens only when the USB hub is powered.
After removing the DC supply plug from the USB hub, I can switch off
the PC fully as normal.

In fact, that's what I'm going to do for the time being, because I
can't get the device (for which I bought the powered hub) to work
anyway. It's a 'Digital Blue QX3 Computer Microscope', and, after
installing software and drivers from its CD, refuses to communicate
with my XP PC ;-[

I suspect the Hub is defective, as Paul mentioned, in reference to the
+5V being fed back into the PC and forcing it to stay powered up. It
may have other issues as well with data transfer. RMA may be the only
answer.

Rob

 

[Terry Pinnell]

It sounds like the +5V on the self powered hub is flowing backwards
into the computer, and keeping the +5V charged. All devices that source
power into a shared power bus, should use a Schottky diode in series
with their power "contribution", to keep this sort of thing from
happening. I don't know how you can fix this as an end user.


+5V +5V
| |
____ ----
\/ \/
-- --
| Cable |
|_____________________________|

You would think there would be one port on the hub, intended for
connection to the host, that wouldn't be self powered (i.e. attempting
to source power).

Paul, Rob,

Many thanks. I'm sure you're right. The same behaviour occurred when I
connected the powered USB hub to my alternative W98 PC in my
shed/workshop. It's incredible that the manufacturer makes no mention
of this fundamental flaw in the accompanying sheet ('User manual'!)

I side-stepped the problem by removing the USB DC supply before using
Turn Off. In fact, I've now removed the powewred hub altogether, as I
can't get the device (Digital Blue QX3 microscope) working on my XP PC
anyway, with or without it. And, after much effort and totally
inconsistent behaviour, I have got it working on my W98 PC, without
the hub.