Does the front right USB port produce more power?

X60/X61 series specific matters only.
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tsammyc
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Does the front right USB port produce more power?

#1 Post by tsammyc » Sun Jul 30, 2006 7:27 pm

I recently bought a HL GMA-4082N slim DVD writer and put it into a USB 2.0 case. The shop assured me that it would work with the X60s without an external power adapter and a single USB cable. It does, but only on the X60s' right front USB port. It is recognised on the other two ports, but will fail to spin up a disk with the light flashing madly. On the front right USB port, it works perfectly, burning DVDs, watching movies etc without any external power.

I therefore conclude that the front right USB port on the X60s is providing more power than the other two. I tried it on two desktops (Dell and Asus) and it won't recognise discs either unless external power is applied so their USB ports are also not strong enough to support the drive.

dorin
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#2 Post by dorin » Mon Jul 31, 2006 12:11 am

besides checking the manual ask some people who have x60 and a voltmeter to check it, its safest.

for me this was the only disapointment ever from ibm swiss, they've told me the special usb connector on my x40 provides 5v and when i bought a voltmeter....15v... :)

so safest is to check it, so anybody could help him?

dorin
X40 (2386H6G) 1.4Ghz 1.5Gb 40Gb

christopher_wolf
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Re: Does the front right USB port produce more power?

#3 Post by christopher_wolf » Mon Jul 31, 2006 1:28 am

tsammyc wrote:I recently bought a HL GMA-4082N slim DVD writer and put it into a USB 2.0 case. The shop assured me that it would work with the X60s without an external power adapter and a single USB cable. It does, but only on the X60s' right front USB port. It is recognised on the other two ports, but will fail to spin up a disk with the light flashing madly. On the front right USB port, it works perfectly, burning DVDs, watching movies etc without any external power.

I therefore conclude that the front right USB port on the X60s is providing more power than the other two. I tried it on two desktops (Dell and Asus) and it won't recognise discs either unless external power is applied so their USB ports are also not strong enough to support the drive.
I have seen this happen on some ultra-portables and it might chalk itself up to be an active power shuttling system. Although the USB standard states you can only have a maximum of 500mA at a set voltage, that is only *if* the host controller and the device can negotiate it out as such (the worst case here would be a device that simply uses the USB for power and doesn't negotiate with the controller). So it could be that that port is managed in such a way as to protect the other ports from devices that would require more power and don't really negotiate the power states correctly.
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tsammyc
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#4 Post by tsammyc » Mon Jul 31, 2006 4:15 am

dorin wrote:besides checking the manual ask some people who have x60 and a voltmeter to check it, its safest.

for me this was the only disapointment ever from ibm swiss, they've told me the special usb connector on my x40 provides 5v and when i bought a voltmeter....15v... :)

so safest is to check it, so anybody could help him?

dorin
On the X40, I had that problem two years ago. I connected it up to a USB DVD and it blew (fortunately there was a fuse).

dorin
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#5 Post by dorin » Wed Aug 02, 2006 4:13 pm

what blew? the dvd? and what fuse are you talking about? unfortunately i remain pretty much in history, i remember the old times when providing twice the required voltage would just fried the unit, 3 times you;d have a very nice expensive pan.

just wanna know more... :)

dorin
X40 (2386H6G) 1.4Ghz 1.5Gb 40Gb

smvp6459
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Re: Does the front right USB port produce more power?

#6 Post by smvp6459 » Wed Aug 02, 2006 5:54 pm

tsammyc wrote:I therefore conclude that the front right USB port on the X60s is providing more power than the other two.
I tried it on my X60s with my slim DVD-RW...you seem to be correct. On the left side I couldn't spin up a music CD but on the right front USB I could. It looks like it must be a high/higher powered USB port. That was with the laptop plugged in; I didn't check it on battery, which might change things - who knows. Sadly, I have no voltmeter to confirm my anecdote.

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#7 Post by jgsx » Wed Aug 02, 2006 7:37 pm

Cheking the voltage won't prove anything. All three ports output 5V. What is important is the maximum current that they can output

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#8 Post by Saml01 » Thu Aug 03, 2006 10:03 am

jgsx wrote:Cheking the voltage won't prove anything. All three ports output 5V. What is important is the maximum current that they can output
yea this is very true. My Dell 700M could spin up an external harddrive, but my 17inch PB could not.
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tsammyc
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#9 Post by tsammyc » Fri Aug 04, 2006 5:46 am

dorin wrote:what blew? the dvd? and what fuse are you talking about? unfortunately i remain pretty much in history, i remember the old times when providing twice the required voltage would just fried the unit, 3 times you;d have a very nice expensive pan.

just wanna know more... :)

dorin
The fuse in the slim dvd writer blew

tsammyc
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Re: Does the front right USB port produce more power?

#10 Post by tsammyc » Fri Aug 04, 2006 5:48 am

smvp6459 wrote:
tsammyc wrote:I therefore conclude that the front right USB port on the X60s is providing more power than the other two.
I tried it on my X60s with my slim DVD-RW...you seem to be correct. On the left side I couldn't spin up a music CD but on the right front USB I could. It looks like it must be a high/higher powered USB port. That was with the laptop plugged in; I didn't check it on battery, which might change things - who knows. Sadly, I have no voltmeter to confirm my anecdote.
Thats great that you confirmed it. Can you burn on it. If not, you might want to try the HL GMA-4082N drive. It burns DVDs great off a singe usb cable and can be made region free

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