USB Issues with External Drive and Keyboard

I hope someone can help me with this. My Seagate 1TB USB external drive is used as my Time Machine on my Early 2008 MacPro. Recently, the drive has been suddenly disappearing from the desktop with a warning that the drive was not ejected properly. Strangely the other thing which happens at this time is that the keyboard stops working. A restart does normally fix the issue but it is happening quite frequently now. I am baffled as I could possibly explain each of these issues independently but if anyone can explain why these issues happen at the same time, I may be able to get to the bottom of why this is happening in the first place. Thanks

USB Ports

Thank you so much for this Loa. The external drive is plugged into a USB Hub which connects to the USB port on the front of the MacPro - the USB port which is just below the power switch. The keyboard is plugged into the USB port on the back of my Apple Cinema Display which in turn, is connected to the USB port on the back of the MacPro via the Apple Cinema Display cable. I suspect that the external drive may be the problem as it may be faulty. I can accept that if this is the case, the drive could and would disappear occasionally but I cannot understand why this would have an effect on the keyboard. Do you have any thoughts on that?

Loa said:

Hello,

+1 on what DCG said.



We might think of USB as a very simple and efficient bus, but like all technologies it has its kinks. USB's main one is hubs: some work great while others are crap. Advice #1: don't use them. Advice #2: if you must use them, use powered ones and don't get the cheapest.

Loa

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Thanks for this advice. I am very grateful for you taking the time. Everything has been working well for ages. I totally agree with your comments re the hub but it is a powered one and I bought the very best I could at the time. My plan after your comments is to replace both the hub and the external drive but I am still totally baffled as to why a fault on a USB device plugged into one side of the MacPro could have an effect on another device plugged into the USB on the other side of the MacPro. Does anyone have a theory on this?

ColdCase said:

When my video card started to go bad, it affected the USB devices, then external SATA drives, then FW devices, then internal drives. It took several weeks for the screen anomalies to start showing up. Dunno if the video card was drawing more power or interfering with the PCI bus.

I had a FW drive act up once that affected both the FW and USB buses.

All USB ports are not connected separately to the CPU, there are a couple buses and host controllers each serving more than one port so devices on one port can and will often affect other devices. Also the power is distributed across USB and firewire. A device or two that draws down power can affect the integrity of the data interface.


Anyway I'm not of much help. But just saying that my system was stable for three years and when USB and eSATA drives started to disappear, I also purchased replacement drives (cheap enough) only to find in the end that it was not a drive or even a USB issue. I now have a plethora of drives.. and have so many backups that recovery may not be all that straight forward

Click to expand...

Now that is actually very interesting. Does anyone know how I can find/use the Apple Hardware Tester. I followed the instructions in Apple Support about restarting and holding down the D key but had no luck. I am using 10.8.2 Mountain Lion and can't find the Hardware Tester anywhere. Do you think this might pick up any faults which are causing my current issues. I have just ordered a new drive and a hub just to be safe. Doh!

Loa said:

Hello,

I'm assuming you found and read this.

I've never tried it, but there are other tools available that Apple doesn't really want us to have: Apple Service Diagnostic.

Not easy to find, and you need the one made specifically for your computer. That app will run very deep tests.

Then again, getting rid of that hub will probably fix your issues...

Loa

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So here is what happened. I bought a new powered hub, a new external drive and a new keyboard. Installed them and sat back very smug assuming that my problems were solved. Later the same day, exactly the same issue occurred again. Doh! Time Machine drive quit unexpectedly with an error message saying it had been ejected incorrectly and at the same time, the keyboard stopped functioning! Doh!

So an hour and a half with an Apple Senior Tech Support guy at £35 for a single incident support call (all my Macs have had Apple Care Extended Support contracts but of course the Mac Pro is just 7 months out of this!) and it seems like we may have solved it - although I still need to watch for a reoccurrence. So here is what I did.

When trouble shooting the issue myself I, of course, reset the SMC by unplugging everything including the power cord and then plugging everything back in. However, we did this again but this time the Tech guy told me to hold in the power button for 5 seconds after everything - including the power cord - was disconnected. Apparently this ensures that all the electricity is dumped from the boards inside the Mac and ensures that the SMC will have been fully reset.

I won't bore you with how I know that this made a difference but trust me it did.

Lesson learned. Hope it helps someone else.