External HD connection issue

[forrestmc4]

Earlier this week I threw a 120GB SATA WD 2.5 inch HD that I had sitting around into an OWC USB 2.0 enclosure. I formated it in HFS with journaling enabled. It works just fine when I plug it into my computer but it doesn't even show up when I connect it to another mac. I can hear the drive making a soft, repeated whir and click sound but nothing else happens. I have already tried reformatting the drive since it was empty to begin with. Thoughts?

[itickings]

Since it is a 2.5" drive, is the enclosure by any chance bus powered (ie only USB-cable connected, no additional power source)?

The sound and situation described is usually due to too little power supplied through the USB cable. Plugging the drive into another power source has so far always solved those problems for me.

[forrestmc4]

I thought it was a power supply issue as well but that doesn't explain why it works just fine plugged into my macbook without a power supply and not our G5 or an mbp.

Edit: I just looked the drive and it draws 550 mA while the bus claims to supply only 500mA so it is possible that my bus is somehow giving it just over 500mA and enough to function properly.

[forrestmc4]

But the OWC website says this: Power Supply
Bus Power via USB on all models with USB 2.0 port factory stock, or any system via add-on USB 1.1 or USB 2.0 PCI Card.
Use of an AC Adapter is optional (and not included), units are designed for Bus Power and do not require the use of external power source.

[itickings]

I thought it was a power supply issue as well but that doesn't explain why it works just fine plugged into my macbook without a power supply and not our G5 or an mbp.

I disagree. Different computers may supply different amounts of power. My computer at work used to work with bus powered drives, but stopped a while ago. It still works if I plug in the drive with an additional power supply.

But the OWC website says this: Power Supply
Bus Power via USB on all models with USB 2.0 port factory stock, or any system via add-on USB 1.1 or USB 2.0 PCI Card.
Use of an AC Adapter is optional (and not included), units are designed for Bus Power and do not require the use of external power source.

Yeah, it is supposed to work if it gets 500mA. If the drive draws more (manufacturing mistake/lemon) or the computer supplies less, it may not work.

[forrestmc4]

Thanks for the replies.