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can mbp power usb ext drive

G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
hi ppl

well i just discovered like many others that my powerbook g4 rev d will not power up a external usb 2.5 harddrive enclosure via a single usb port !!

This is a known problem according to macintouch because the pb can only supply 5v max via usb where as an ibook can supply more and usb hardrdives function fine with it !!!

I know because this enclosure worked fine on that machine (ibook g4) !!

anyway my question is can the macbook pro power usb hard drives via a single usb port leaveing the other usb port spare for data or does it suffer from the same issue as the powerbook ???

I have called apple and they claim that they dont know of this problem which is b.s as its all over the net (google powerbook usb issues)

can someone with a macbook pro test to see whether it can power up a usb harddrive through one usb port ???

I cant even use a splitter cable because then i have no more usb ports to use for data as both ports are occupied trying to power the thing up !!!

i used to use my ibook on my travels (student) but thats sold now so if the mbp doesnt have this problem then i will demand my pb get replaced for a mbp as these machines (pb) are supposed to be portable not disabled and what the fk the ibook can perform this function while a high end pro machine cant ???

come on apple !!!!
 
miles01110

miles01110

macrumors Core
Jul 24, 2006
19,260
37
The Ivory Tower (I'm not coming down)
Um, a hard drive consumes a lot of power for a USB port to handle honestly. I'm not sure what the specs are for the powered USB ports on the MBP, but it's not unreasonable that Apple did away with that feature to increase battery life.
 
Bill Gates

Bill Gates

macrumors 68030
Jun 21, 2006
2,500
14
127.0.0.1
miles01110 said:
Um, a hard drive consumes a lot of power for a USB port to handle honestly. I'm not sure what the specs are for the powered USB ports on the MBP, but it's not unreasonable that Apple did away with that feature to increase battery life.
Click to expand...
That should be for the user, not Apple, to decide.
 
Sun Baked

Sun Baked

macrumors G5
May 19, 2002
14,941
162
Important: Peripherals such as PCMCIA cards and USB devices that do not conform to the computer’s power management protocols prevent the computer from switching to sleep state and so deny the user the benefits of this energy-saving state.

&

http://developer.apple.com/qa/hw/hw82.html
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

well i already called apple so i will call again to push this matter through !!!
it must be a problem they know about because they have corrected it in the new macbook pro's so ppl how can i get applecare to repalce my pb for a mbp seen as the pb is no good to me on my travels ???

£1400 for a disabled product

great :rolleyes:
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

the user has made the choice already !! like me !! By paying soo much over the odds for a PRO product , but that doesnt mean we as the user will expect anything less than perfect !!!!
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

i seem to have hit upon something maybe ????
when i use a 5v ac the harddrive works fine !!!!
so the problem must be the ports not supplying the full 5v which is fckd up the thing should supply that voltage as its the spec for the usb port :mad:

applecare for **** sake :confused:
 
P

persep

macrumors member
Sep 12, 2006
56
0
Spain
Gokhan said:
i seem to have hit upon something maybe ????
when i use a 5v ac the harddrive works fine !!!!
so the problem must be the ports not supplying the full 5v which is fckd up the thing should supply that voltage as its the spec for the usb port :mad:

applecare for **** sake :confused:
Click to expand...

Hi,
it's got to do more with the current rather than the voltage.
The USB 1.1 and 2.0 specification requires that each USB port delivers at least 500 mA of steady-state current; however the
majority of systems provide 700 mA of steady-state current but not the 15" and 17" PowerBook. Most 2.5-inch disc drives meet this requirement only after they are
already spinning and usually require a higher current during the initial spin-up profile. The majority of USB ports also allows for
a higher current draw of 1000 to 1100 mA for a limited duration (instantaneous current) that allows the disc drive to spin up
adequately. This capability varies from PC to PC and depends on a variety of factors such as the type of USB port, the USB
controller used, the type of regulator and the type of capacitors at the host.

You have the full explanation here http://www.seagate.com/docs/pdf/whitepaper/TP-535.pdf

There was a post in the Apple forums from a guy from LaCie that could confirm this current limitation is to protect the laptop from external devices. Why didn't Apple use this protection scheme in their other computers beats me.

The work around fixes are:
- use firewire ( when the powerbook came out Apple was pro-firewire not pro-usb2)
- use a Y usb cable, it' a usb cable with two plugs, one for data and power and the other one only for power)
- use a selfpowered harddisk enclosure not buspowered
 
sycho

sycho

macrumors 6502a
Oct 7, 2006
865
4
persep said:
The work around fixes are:
- use firewire ( when the powerbook came out Apple was pro-firewire not pro-usb2)
- use a Y usb cable, it' a usb cable with two plugs, one for data and power and the other one only for power)
- use a selfpowered harddisk enclosure not buspowered
Click to expand...
All of those are really the best choice for a laptop. I would be careful pulling more then 250mA from a USB port, never mind 700mA, they are just not designed to source that much current. Firewire would most likely be the best option, since it can provide upto 48volts, I believe, not sure how much current, but it should also not use as much CPU time as USB.
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

yeah but why do i as a pro consumer have to suffer from fckd usb ports i know i could use firewire but again i have to fork out extra for a firewire drive ???

nah the simple work around for me anyways is a new machine that does what i want and paid for to use the machine as a PORTABLE laptop!!!

This is not cheap pc crap its top of line ! why should i have to compromise :mad:
 
Grakkle

Grakkle

macrumors 6502a
Oct 6, 2006
624
2
Earth
I use a Blue Snowball usb-powered mic with my macbook, and it works fine. Sucks battery power fast, though, so I usually plug in the macbook when I use it. I'd think the mic would use as much or more power than a hd.
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

the guy at apple was away and ill call next week because i want to speak with him personally but i may even just sell the powerbook on ebay if the price is right !!!

but thats the last apple laptop for a while for me ! they are just too much high maintence

sorry but they are :)
 
P

persep

macrumors member
Sep 12, 2006
56
0
Spain
I know what you mean. you'd expect a perfect laptop for that price and what you is nothing near it.
 
G

Gokhan

macrumors 6502a
Original poster
Oct 7, 2003
703
0
London
k

yep you get the elements to get the thing perfect but im just sick of having to correct apples mistake's software and hardware wise
 
J

jtown

macrumors 6502
Jul 3, 2003
306
0
Why get mad at Apple because a third party product doesn't conform to the published specifications of the USB interface? The specs are very clear. 5 volts, 500ma. If a device exceeds those specs, why rant at Apple? It doesn't make any sense. Go complain to the companies selling these external drives as "USB Powered" when the description is clearly misleading.

Why do you think all those 2.5" USB drives have ports for power adapters? Because those manufacturers know that their devices exceed the limits of the USB specification. If the drives could work reliably on 500ma, those drives would not be designed to accept power adapters.
 
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