VRM fried on Cube?

Discussion in 'Macintosh Computers' started by livingfortoday, Oct 20, 2005.

  1. macrumors 68030

    Okay, I have a problem, which if you've been following my Cube-related adventures, should come as no surprise.

    I installed my Powerlogix Dual 1.5Ghz CPU upgrade into my Cube, and everything booted up right, and I was able to even run Folding and whatnot, without a hitch. I then shut down, because I wanted to install the fan that came with the upgrade, in the place of the one I had put in there a few months back. Mine was set up with a y-splitter and plugged into the power from the hard drive, so I took that all out and set it back to normal, and plugged in the Powerlogix fan which got power from the VRM fan-plug thingie.

    I then tried to boot up, but nothing happened. There was a faint burning smell, and then the power light went out. The power light won't come on any more, no matter what I do. I opened up the Cube, and the VRM has a green light whenever the Cube is plugged in, so I guess there is power going to it. The power switch won't light up, though. I checked all the cables, and everything's attached properly still.

    I'm afraid that maybe the VRM burned out due to the new CPU, but the upgrade had a VRM bypass cable and everything which I installed. Is there a way to try to boot up the computer without the front switch? I know on a PC I can touch the jumpers on the motherboard to boot it up, is there an equivalent on the Cube?

    And if that won't work... how do I tell if my VRM is fried? And could the fan have caused this? I tried taking out their fan and setting back my old one, but still nothing works.

    Any help would be very appreciated!!

    Oh, and here's a quick screenshot I had taken before the Cube died... help me bring it back to its former glory!

    Attached Files:

  2. macrumors P6

    IJ Reilly

    Difficult to say, but if I were you I'd probably swap the original CPU back into the Cube. I know this is a lot of work, but it will rule out a defective board. I suppose if you had multitester and knew what and where to test, you might be able to diagnose what power is getting to where.

    The VRM should not burn out simply due to the upgrade install. And, as you know, the PowerLogix boards have that VRM bypass thing, so this seems even less likely as a cause.

    If you've got a ADC display and video card (which I image you don't) then you can start the Cube from the button on the display.

    You might also try this question over at cubeowner.com. You're more likely to run into someone who's encountered this problem.

    Of course you can also call PowerLogix....
  3. macrumors 68030

    Thanks, yeah, i figured I should try to reinstall the original processor... blargh. So much effort.

    Okay, I'm gonna go try that out, and I'll be back!
  4. macrumors 68030

    Alright, put the 500Mhz back in, made sure everything was hooked up right... and still nothing. The green VRM light turns on, but nothing else. I guess this rules out the processor upgrade being messed up, but damn, the VRM is a pricey piece to fix if it is that.

    Any other ideas?
  5. macrumors P6

    IJ Reilly

    Sorry, I'm stumped. I recommend the boards at cubeowner. One of the Cube veterans over there can probably point you in the right direction.

    I'm pretty sure the VRM can be bought for not a great deal of money, as a used part. If that's what it turns out to be, of course.

    One other thing: did you reset the CUDA switch?

    It's a long shot, but...
  6. macrumors 68030

    Yeah, I reset it. Dang, ok, I'm gonna head over to Cubeowner and see if they can figure it out. Thanks for your help!
  7. macrumors 68030

    Oh yeah, and I got this response from Powerlogix to my same question this morning:

    "Sounds like you may have fried the dc/dc board."

    So I guess they're kinda on the same wavelength as me. i just wish they' offer some sort of assistance as well, seeing as it's most likely their product that broke my Cube... ah hell, I'll deal with it.

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