Thursday, June 28, 2012

Zalman ZM-VE200 Enclosure Power Fix

The Zalman ZM-VE200 enclosure is unique because it offers a cdrom simulation mode.  Basically you create a folder called _iso on the root of the drive, put ISOs in it, and with the toggle switch on the unit you can select an ISO to load as a cdrom drive. This is great for installing an OS or booting off ANY CD.  While lot of Linux distros and other software may have a way to make a USB boot drive, not all CD/DVD can simply be "burnt" to a USB drive.  So for example if you want to install a legacy operating system like windows 98, you need a CD.  But what if all you have is an ISO and you don't want to burn a CD for only this one time?  This drive comes in handy.  Put away all your CDs, and store the ISOs on here (and a backup elsewhere of course) and you'll never have to start looking for a CD again. 

This is great for trying out different Linux distros as well, it's much easier to just download the ISO, then to go through a USB stick conversion tool and all that given ISOs are universal so anything will usually be available in that format.

Now here comes the issue with this drive, for some reason the designers thought that USB alone would be powerful enough to power a hard drive.  WRONG!!  It is barely enough, unless you happen to hit a port that has more power than the standard.  Since this device is made to use on different computers, you don't want to rely on that.  By design USB provides about 500ma of power.  A 2.5" hard drive will typically need about 550ma.  That's cutting it close, especially when you consider that the enclosure's controller itself needs power too.   So what often happens is the drive will fail to spin up, or it will spin up, but the transfers will be very sloppy and it will also completely fail and spin down. 

The solution?

MORE POWER!!!!!11!!    Just inject more power into the USB! 

I sliced the USB cable, located the red (+5v) and black (ground) wires, sliced it without cutting it in half, and carefully soldered the positive and negative of a power adapter as to add more power.    I could have done this at the sata level that way I'm leaving USB alone, but this was cleaner as I can keep the drive in the enclosure.

I tested this on a computer that did have trouble running it before, and it ran fine.  It seems on newer machines it's less of an issue, but on older ones it is an issue.

Now, you'd think Zalman would have included a port on the enclosure to plug a 5v adapter. 

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