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External optical drive woes

My old laptop, a Dell Latitude E6510, has a bad DVD drive. It won’t read most discs, and almost everything I try to burn, fails. I purchased an external USB drive to use with it, and that works well. It was cheaper than replacing the drive itself. Replacing the drive is straightforward, I just don’t want to spend the money right now to get a new drive.

About a week ago I wanted to install some software from a CD (Who does that anymore, right?) on my Asus tablet, which lacks an optical drive, but has a USB port. I plugged the external USB drive into the port, and put the disc in it. Shortly after, the drive kept disappearing from ‘My Computer’, I kept hearing the Windows disconnect and reconnect sounds. It wouldn’t stay ‘connected.’

My son likes to get into things that he shouldn’t, so I nearly chewed him out for it straight away, but after taking a bit to calm down, I decided to troubleshoot. I thought it was a bad cable at first, so I tried a few different cables. No change. Tried wiggling the USB port to see if the tablet port was faulty, no change. I plugged the drive back into the Dell, and it worked without a problem. This got me thinking.

After some of that thinking, I finally figured out what the issue was, and I’m posting this to see if anyone else can figure it out too, because you’ll learn something from my ordeal. Something that may surprise you.

This is a photo of the bottom of the USB drive, showing the label and the USB plug. Most of the information you need to figure this out is in this photo. You may need to go and do a web search if you’re missing a piece of information.

Post your comments, questions, or guesses in the comments below. The first person who figures it out will get recognition, and I’ll clarify the answer if it needs any. 

Hint: Again, almost everything you need to know to figure this out is in the photo of the USB drive. Almost. The rest is a quick web search away.

Hint: The Dell laptop has USB 2.0 ports. The tablet has USB 3.0. This is not the reason, although it’s going in the right direction. 

Guess/Hint: Someone guessed that the drive was made on April Fool’s Day. A clever guess sir, but not correct. You are looking in the right area.

Guess: Someone guessed that I might have been using the microUSB “On The Go” (OTG) port. A good guess, as this tablet has one of those ports as well, but no. I was using the USB 3 port that’s on the tablet’s keyboard dock. I did just try using the OTG port instead of the USB 3.0 port and got the same result. I am not surprised. 

Here are photos. Click any for a larger image:

Answer: My friend Gary got the idea that it might have been a power issue, but cwyenberg went so far as to point that 1.6A is a lot for a USB draw. 

Explanation: From Wikipedia:

USB power standards
Specification Current Voltage Power
USB 1.x and 2.0 500 mA[a] 5 V 2.5 W
USB 3.x 900 mA[b] 5 V 4.5 W

USB devices can only ask for so much power, (up to 500mA for a USB 2.0 device), and 1.6A is far beyond that. This drive can’t be expected to work under all circumstances according to the USB specification. The reason that it worked on the Dell laptop is probably that Dell is allowing the device to draw more power for the sake of compatibility. This is why you see external hard drives with Y-cables — the device can pull from 2 USB ports to get more power and still adhere to the USB standard, allowing the device to be expected to work under all circumstances. Interestingly enough, the drive does work with a powered USB hub rated for 2.5A. So, if you’re having a similar issue as me, try getting a powered USB hub. 

There’s a handy program I found called USBTreeView that can show you the requested power for each device connected to your USB bus. In this case, USBTreeView shows the following lines for this drive:

iManufacturer : 0x01
Language 0x0409 : "Hitachi-LG Data Storage Inc"
iProduct : 0x02
Language 0x0409 : "Portable Super Multi Drive"
...
MaxPower : 0xFA (500 mA)

Thanks for reading (and for your responses)!

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  1. #1 by cwyenberg on January 13, 2015 - 7:23 pm

    Not enough power on the Asus tablet USB 3 port? External DVD draws 5V @1.6A…seems like a lot for a tablet port. Sorry if I’ve double posted, had log in issues with the first post.

    • #2 by Mike Beach on January 13, 2015 - 7:38 pm

      Absolutely correct. Not only is it a lot for a USB3 port, but its over the spec limit of 900mA. My guess is that it works on the Dell laptop because Dell allowed the ports to draw more power beyond the spec.

  2. #3 by Clint on January 14, 2015 - 12:36 am

    You could tap into both USB 3 and micro USB otg using a split usb cable and adapter…

    http://amzn.com/B003WV5DMO and http://amzn.com/B005QX7KYU or similar depending on how your ports are situated.

    The combo should give you the necessary power

  3. #4 by cwyenberg on January 14, 2015 - 12:39 am

    You could tap into both USB 3 and micro USB OTG using a split usb cable and adapter…

    http://amzn.com/B003WV5DMO and http://amzn.com/B005QX7KYU or similar depending on how your ports are situated.

    I’m not familiar with the microUSB OTG port spec but I would think the combo would give you the necessary power

    • #5 by Mike Beach on January 14, 2015 - 6:31 am

      I have the OTG adapters already, but the USB Y-cable I do have doesn’t reach. For some reason I can’t find my USB extension cable at the moment. I’ll have to try it once I do find it.