Power Supply and USB power draw

Discussion in 'Power Supplies and UPS's' started by Grizz77, Aug 5, 2010.

  1. Grizz77

    Grizz77 Geek Trainee

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    Hi folks,

    Hoping someone can shed some light on how USB devices affect the total power draw of a system. I'm 99% sure that my crappy Echostar imitation PSU is just dying a slow death, but I was curious as to whether having too many USB-powered devices plugged in can stress a power supply. I have a piano keyboard, sample pad, and an audio interface that are all powered solely by USB, so I'm wondering if, with everything else the PSU is powering, my USB devices are trying to draw more power than my PSU can supply.

    The problem started with random BSODs of the "SYSTEM_SERVICE_EXCEPTION" variety. No specific files specified on the screen. Just a memory location. Sometimes it would get stuck in a loop when rebooting. It would fire up, then about 4-5 seconds later, shut down, then fire up again for 4-5 seconds and shut down, etc. I tried plugging it into a power conditioner, thinking that maybe something was up with the power from the wall (I'm in southern California... brownouts are our specialty). That worked a few times, if only by coincidence, but now it won't even boot. I just get a beep code. Looked it up in my motherboard book and apparently it's a power issue. Doing a little research, I found that my 600W Blue Star is just a rebrand of an Echostar PSU, which are cheap pieces of garbage (Makalu's review of an Echostar 680W).

    Does my assessment sound right? Can I be reasonably certain that this is all related to a failing PSU? Will the USB bus allow devices to draw more power than a PSU can support?

    Any insight into this issue is MUCH appreciated.
     
  2. RHochstenbach

    RHochstenbach Administrator

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    Welcome to HWF :)

    USB 2.0 has a maximum output of 500mA, which is just a few Watts. So the USB power consumption can be ignored.

    But it sounds like a problem with your PSU indeed. Cheap Power Supplies can break down easily, just as that review confirms about that specific PSU.
     
  3. Grizz77

    Grizz77 Geek Trainee

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    Thanks so much, RH. I just picked up a Corsair CMPSU850TX and will be installing it today or tomorrow. ...hoping my craptastic Blue Star didn't damage anything else in the case during the final stages of its miserable existence...
     

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