PCMCIA/Cardbus USB and power

[sojourner]

Knowing about the USB port failures it seems T-series notebooks often have, I tried my Cardbus USB adapter with an external HDD (no external power) and the HDD does not work, can't even hear it spin up.

I know the external HDD and cable (three connectors, pigtail) are good because the setup works perfectly when using the notebooks two built-in USB ports.

It seems the adapter is fine because the mouse, webcam etc work fine in its USB ports (just the HDD won't start).

Questions:
1. is there a particular brand of PCMCIA USB adapter which can provide the 500ma per port which is needed for powering the HDD? Would prefer to NOT need external power.
2. Can a ThinkPad T41 even provide the 500ma per port needed from its internal PCMCIA/Cardbus connector?

Thanks

[mgo]

Knowing about the USB port failures it seems T-series notebooks often have, I tried my Cardbus USB adapter with an external HDD (no external power) and the HDD does not work, can't even hear it spin up.

Here is what I have discovered about using pc cards and usb drives:

1: plug in the pc card and let the computer install the drivers for it. (that usually happens automatically with XP and Vista, since the drivers are already within the operating system driver library.
2: remove the pc card, using "safe to remove" or "easy eject"
3: while the pc card is out, plug in the usb hard drive. Then plug the pc card into the computer slot. The usb drive will now get bus power and should run.

If I plug in the pc card, and then plug in the usb drive, there is no bus power for the usb drive. There may be some sort of "logic" in the pc card firmware to detect a usb drive, but only if it is plugged in first.

[sojourner]

while the pc card is out, plug in the usb hard drive. Then plug the pc card into the computer slot. The usb drive will now get bus power and should run.

If I plug in the pc card, and then plug in the usb drive, there is no bus power for the usb drive. There may be some sort of "logic" in the pc card firmware to detect a usb drive, but only if it is plugged in first.

mgo, tried doing what you said but it did not work! I found reading through ebay ad's for adapters some people say their card provides 500ma to each port, others make no such claim! Can it be some cards do not provide 500ma per port? That's what is needed to start this HDD (200GB Toshiba). Can it be the adapter chipset used makes a difference? (mine is by VIA)

Sure wouldn't want to spend more mony for another card but if I must, then will.

Hoping others will answer with their experience.

[mgo]

Can it be some cards do not provide 500ma per port? That's what is needed to start this HDD (200GB Toshiba). Can it be the adapter chipset used makes a difference? (mine is by VIA)

The specific card I am using is from Best Buy. It is the "Dynex 2 port USB 2.0 Card Bus Adapter"

Model number is: DX-UC202

I am running as large as 120 gig Hitachi or Western Digital drives. I also have a couple of much larger 3.5 inch drives but they have their own power supplies.

hope this helps...

[virge]

I have a USB external HDD that has a similar problem on my desktop. It works with the USB ports built into the motherboard, but not with the USB ports I added through a PCI card.

Turns out that the USB ports on the PCI card weren't putting out enough juice to spin up the HDD. With the HDD removed and just plugging in the empty enclosure, the enclosure powered up fine. I ended up swapping some USB devices to work around the problem.

Have you tried a different drive? Some drives take more juice than others it seems like.

[sojourner]

Have you tried a different drive? Some drives take more juice than others it seems like.

I have not tried a different drive (and agree some take more 'juice' than others) but think I may have a clue as to what's going on. If my understanding is correct the Cardbus slot has 3.3v for power (not 5v). If this is true then the card (adapter) needs to have a DC-DC up-converter to transform 3.3v to 5v (which USB needs) AND it needs to be able to provide the current of 500ma to each port. SO, maybe some cards are not so robust as to be able to do this technological feat, some may be. Handling a mouse or webcam etc takes very little current, maybe 100ma ... a long cry from 500ma. These cheap cards may be able to handle low current for common devices but fall down when really called on like when a HDD needs to spin-up. Unfortunately the adapter I bought did not advertise 500ma per port. Maybe it can't do it!

Would sure like to hear from those who have an adapter which advertises 500ma per port and allows operation of an external HDD! (and please let us know the brand/model)