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Brand new iMac (21.5") USB mystery

S

sPaCePiR8

macrumors newbie
Original poster
Feb 4, 2015
5
0
Hello forum,

I've been using Macs for over 10 years now, so far never had a problem which couldn't be solved but now it seems I've reached a point where this is no longer the case.

Have a new iMac (21.5", 3.1GHz, 1TB Fusion Drive) since a few days. Everything's working fine, apart from the USB ports. A few examples below:

- iPad working perfectly fine (i.e. charging and being recognized in iTunes) when using an original Apple Lightning cable
- iPad alternating between "plugged-in" mode and "plugged-out" mode constantly when using a non-Apple Lightning cable (tried no name ones as well as Belkin ones - same result). The same no name or Belkin cable however works fine when charging iPad using the (original Apple) wall plug
- iPhone works perfectly fine with no name / Belkin and Apple Lightning cable
- 2.5" USB 2.0 portable hard drive works perfectly fine
- 3.5" external hard drive (in case, externally powered) works perfectly fine over FireWire800 via Thunderbolt adapter
- the same 3.5" external hard drive does not work over USB 3.0 (external case has 2 FW800 and one USB 3.0 plug). Whenever I plug it in using the USB 3.0 it appears in the Finder for a few seconds, then an error message pops up saying I should unmount the drive properly before ejecting. It also shows up in the disk utility within the first few seconds but then disappears. Have tried a few cables and all four USB ports and it's the same for all of them

Have searched the web quite extensively, many people seem to have problems with USB 3.0 drives when the Mac goes to sleep but my problem pops up immediately after I plug the drive in. When I first tried it I thought the USBs might be faulty but they work perfectly fine with the iPhone and the old USB 2.0 external HD

Any thoughts on this? Thanks in advance
 
I thought of that as well but as I said, it works absolutely fine on the FireWire/Thunderbolt port. Disk Utility also doesn't show any problems. The HDD inside is also just a few weeks old.
 
dyt1983 said:
That only proves that the FW interface works fine. His point was that maybe the USB interface on your enclosure is bad. Also, those that use USB 3 micro-B connectors are known to sometimes have flaky cables and ports. Those that use standard B connectors generally don't have such a problem. Which is yours?

If the drive works fine through USB on another Mac, then you have pinpointed it to your machine. Until then it is speculation.
Click to expand...

Thanks, makes sense. I will try and check on another Mac tonight.
The USB 3.0 is a standard connector (like this one: http://www.techspot.com/articles-info/278/images/3s.jpg), not a micro one
 
sPaCePiR8 said:
Thanks, makes sense. I will try and check on another Mac tonight.
The USB 3.0 is a standard connector (like this one: http://www.techspot.com/articles-info/278/images/3s.jpg), not a micro one
Click to expand...
Did that and the issue is the same - seems to be a problem with the external case then.

Thanks for your help.

Any ideas on the issue with the iPad and non-Apple cables? Since the other error is most likely caused by the case, this seems to be another one on its own
 
[[ - 3.5" external hard drive (in case, externally powered) works perfectly fine over FireWire800 via Thunderbolt adapter
- the same 3.5" external hard drive does not work over USB 3.0 (external case has 2 FW800 and one USB 3.0 plug). Whenever I plug it in using the USB 3.0 it appears in the Finder for a few seconds, then an error message pops up saying I should unmount the drive properly before ejecting. It also shows up in the disk utility within the first few seconds but then disappears. Have tried a few cables and all four USB ports and it's the same for all of them ]]

Does this external drive enclosure have its own power supply, or are you trying to run it off of "bus power" ???

If it has a power supply, try using it. USB3 probably can't supply enough "bus power" to run it on its own...
 
[[ You quoted the first sentence where the OP wrote "externally powered" ]]

Haha, getting too old, can't see, can't read!

I've seen similar "self-ejecting" behavior with some USB enclosures myself.

Doesn't seem to be cable-related or power-supply-related.

I'm thinking it might be glitches in the enclosure's controller chip or board, perhaps with "sleep issues" as well.
 
dyt1983 said:
I have no other explanation other than bad cables. Since it is easily remedied by using original cables, my tack would be to just use original cables and move on. (I admit this course of action sometimes comes back to bite me, but I would rather just get on with it.)
Click to expand...

Thanks - I guess it just hurts to shell out >£15/$20 for a short USB cable...
 
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