mid 2011 27" with external Thunderbolt SSD Power Loss Problem

Discussion in 'iMac' started by bluesummer, Nov 28, 2012.

  1. bluesummer macrumors newbie

    Nov 28, 2012
    Hi all,

    After reading the thunderbolt + GoFlex adapter + SSD setup and a round of black friday shopping, I ended up with a 128GB Crucial M4 and the all the accessaries to complete the upgrade. I finished transferring and worked out some file permission glitches today and started booting completely from the external SSD. Accompanying by 16GB crucial ram, the speeding is amazing.

    However there is one problem I keep on encountering. After a period of time, the computer will shutdown and reboot (since I set it to reboot after power loss) itself due to power loss (according to the error message displayed on the gray screen). It happened to me twice so far since I completely the setup about 12 or so hours ago. Does anyone with the same setup as me have the same problem? Is there any fix?

    Thanks in advance
  2. Tom J, Nov 28, 2012
    Last edited: Nov 28, 2012

    Tom J macrumors regular

    Sep 15, 2006
    Are you refering to the desk Thunderbolt adapter with 2 ports or the sled type portable w/ 1 port?

    The self powered GoFlex portable Thunderbolt adapter is known to be flaky with SSD's. One reason is that some SSD's draw more power than is available causing the Thunderbolt controller to "disconnect" which sounds like what is happening to you. Many reports of these drives disconnecting randomly. It's obviously much worse if you're using it as a boot drive as you are aware.

    The best explanation of the specific issue can be found here.

    I bought two of the portable adapters and took one apart just to see what's going on in there. The Thunderbolt spec allows 10 watts to be delivered to the TB device. However, those 10 Watts have to power the adapter too, and there's A LOT OF STUFF IN THERE. I can see why its a problem.
  3. juliazo macrumors newbie

    Jun 13, 2012
    Sounds like one of the external devices might be causing a short (or drawing too much current, kinda the same thing). The good thing about this is that it all started after making the hardware changes, so it follows that one of the devices added (either the external adapter or one of the RAM modules) should be the culprit. Easiest way to find out is to remove either one and test to see if the issue continues to happen. If it all works well, then put that back and remove the other, and so on. My money is on the RAM.

    Needless to say, when removing the RAM modules, do so in pairs...

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