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Portable External Hard Drive cannot be powered

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As others have mentioned, the problem is startup current exceeding the USB 2.0 spec. USB 2.0 can only deliver 500mA @ 5V (2.5w), but a 2.5" 5400RPM can easily use 4-5w while the platters are being spun up. This leads to some fickle behavior. Works on some boards (and even some USB ports on the same board), but not others. For example, with my Gigabyte the front ports can't power my 2.5" external, but the back handle it fine.

Some newer Gigabyte boards have high current USB ports that are designed to deliver more power, though. USB 3.0 spec also allows for higher current, so these drives should work fine in them. Without replacing your mobo, though, external AC adapter (if you're drive has a plug for one) or powered USB hub is your best bet. 1A @ 5V should be adequate for the AC adapter.
 
Are you sure about the 5v 1A ac adapter? I'd used an AC adapter on this before to power a drive that was going bad and it ended up killing the drive's PCB completely. I'm pretty scared to use a power adapter and I'm pretty sure the power adapter I used before was 5v or 5.5v. Does this enclosure have no fuses as prevention from killing the drive? Some 5v DC adapters go to 4.9 ~ 5.1v
 
I emailed Hitachi about an external AC adapter for my 2.5" 250GB external and they suggested 5V 1A. Maybe other drives would have higher power requirements, though. Also yeah, there would be some fluctuation, but there should be voltage regulation in the drive and/or the enclosure to smooth out any swings. At the very least I'd think the drive should be able to handle ATX spec for 5V, which allows for +/-5% tolerance (so a voltage range of 4.75V to 5.25V).

I mean you said the drive was going bad, maybe its failure was just coincidence and had nothing to do with the adapter you used.
 
frostedflakes said:
I emailed Hitachi about an external AC adapter for my 2.5" 250GB external and they suggested 5V 1A. Maybe other drives would have higher power requirements, though. Also yeah, there would be some fluctuation, but there should be voltage regulation in the drive and/or the enclosure to smooth out any swings. At the very least I'd think the drive should be able to handle ATX spec for 5V, which allows for +/-5% tolerance (so a voltage range of 4.75V to 5.25V).

I mean you said the drive was going bad, maybe its failure was just coincidence and had nothing to do with the adapter you used.
Click to expand...

No because I had data to back up. The drive just had bad sectors. I ended up buying a new PCB and getting the data off the drive. I'll look into a 5v 1a AC adapter. Was there an official one for the Hitachi drive? I'd assume it'd be the same plug for this Antec enclosure.
 
Nah that's the weird thing, the drive had a plug for an external AC adapter, but didn't include one, nor did Hitachi offer one as an accessory that you could buy. Unfortunately I guess customers are on their own to find a compatible one.
 
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