Powered USB2.0 slot

[Steve]

I have a IBM Thinkpad X41 with a powered USB2.0 port running WinXP.
Anyone know if the port has a standard power output and will power an
external DVD/CD rom drive ?
I would like to use an external drive preferably without having to use its
own power supply.
Steve

 

[Jim Macklin]

Take some files you don't care about and can verify their
accuracy, a few simple text files for example, and try some
read and writes. But be aware that you will shorten the
laptop's battery duration and your data may be at risk if
you are doing larger files.


--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm



|I have a IBM Thinkpad X41 with a powered USB2.0 port
running WinXP.
| Anyone know if the port has a standard power output and
will power an
| external DVD/CD rom drive ?
| I would like to use an external drive preferably without
having to use its
| own power supply.
| Steve
|
|

 

[Quaoar]

I have a IBM Thinkpad X41 with a powered USB2.0 port running WinXP.
Anyone know if the port has a standard power output and will power an
external DVD/CD rom drive ?
I would like to use an external drive preferably without having to
use its own power supply.
Steve

No can do. Standard USB port output is 500ma at 5 volts, 2.5 watts.
Startup power alone will likely require more than this and you run the
risk of burning out the port. IMO.

Q

 

[bxf]

For what it's worth: I can use a laptop HDD in an unpowered external
case directly from a USB port on my laptop. HOWEVER, I am also able to
run another device that is supplied with two USB connections (to obtain
power from both, because it uses more than 500ma) using only ONE port.
This tells me that USB ports are not necessarily all created equal.
YMMV.

 

[Yves Leclerc]

Most external DVD/CD drives require way more power than what the USB could
provide.

 

[Quaoar]

For what it's worth: I can use a laptop HDD in an unpowered external
case directly from a USB port on my laptop. HOWEVER, I am also able to
run another device that is supplied with two USB connections (to
obtain
power from both, because it uses more than 500ma) using only ONE port.
This tells me that USB ports are not necessarily all created equal.
YMMV.

This might work for a while, but laptop USB is replete with burned-out
ports from doing this. If the total bus power is from one source,
distributed port to port, you run the risk of burning out the entire
power supply to USB and damaging the mainboard as well. I no longer
connect any power-consuming device to a laptop USB port unless I am
certain that there is minimal risk. Mice, flash drives, etc. are
minimal risk. Drives, even laptop drives, are not minimal risk, IMO.
Even though my external laptop drive works well on port power, it is now
on 5 volt DC. I value my laptop too much to do otherwise.

Q

 

[bxf]

This might work for a while, but laptop USB is replete with burned-out
ports from doing this. If the total bus power is from one source,
distributed port to port, you run the risk of burning out the entire
power supply to USB and damaging the mainboard as well. I no longer
connect any power-consuming device to a laptop USB port unless I am
certain that there is minimal risk. Mice, flash drives, etc. are
minimal risk. Drives, even laptop drives, are not minimal risk, IMO.
Even though my external laptop drive works well on port power, it is now
on 5 volt DC. I value my laptop too much to do otherwise.

This is somewhat worrying, but I've been using this setup for over a
year, so perhaps I need not be overly concerned. In actuality, I use
the external HDD I mentioned only when I have a particular need to
transfer data, not on a day-to-day basis.

As far as I recall, if I try to use my capture device (that is the one
that can draw even over 1000ma, according to some who have tested it)
in a port that cannot provide sufficient power (e.g. another laptop),
it simply does not work. No damage results.