Blown MBox

Discussion in 'Converters / Interfaces' started by taxman, Apr 14, 2009.

  1. taxman

    taxman Active Member

    Sep 22, 2006
    I have a mac mini firewired to two glyph drives and then to an MBox2Pro. The MBox died and I couldn't boot up ProTools because it didn't see any Digi hardware. Digi fixed the box but I still have the same problem. They are now sending me a replacement box.

    One of the Digi techs suggested that my equipment was putting out a bad signal or too much voltage on the firewire line and blowing the power input of the box.

    How can I test this out before I blow another box? If this were true, wouldn't one of the other drives on the firewire daisychain also blow? I have no problem reading from the drives.
    Are there service people who can do this?
    How can I find what nominal specs are for a firewire connection? Is there a way to hook up a scope?

    Thanks. Trying to avoid another eve MBox of destruction.
  2. ahavill

    ahavill Guest

    Firewire devices are very sensitive to being dis/connected. Do you always connect everything in a powered down state, power up the external firewire devices, then power up your computer, AND power down in the reverse order before any disconnections? That might sound unecessarily complicated, & a lot of devices have no problem being hotswapped on a FW port as long as you eject. But "officially" you are supposed to follow the above-mentioned procedure; if you don't, with some devices, you'll burn out the port on your computer or the ext dev. Maybe that's what the Digi tech meant? And, maybe why Apple is phasing out FW even though they invented it... & a lot of us are stuck with it.
  3. TheJackAttack

    TheJackAttack Distinguished Member

    Mar 20, 2008
    currently Billings
    Most newer laptop firewire cards do not pass power at all for this reason regardless of the bus potential. I don't know if there is a way to shut it down on desktop cards or not. I haven't ever tried.

    I blew the 1394a bus on a Siig card once using the Siig ac adapter in an absent minded hotswap. I have since just gone to plugging devices directly to the power conditioner in the Studio Flyer and calling it good.

    I hate those dual usb cords (usb + power) for the same reason.
  4. ahavill

    ahavill Guest

    Forgot to say:
    Are you powering the mBox via the FW bus, or using the external power supply? Also what does Digi say about how you are chaining the interface off the hard drives, I know it works but maybe not a good idea.
    And, if you are concerned about the firewire voltages from your mini, I bet you could take it to a mac store & have them check.
  5. taxman

    taxman Active Member

    Sep 22, 2006
    Digi recommends external hard drives with the MBox as the last item on the chain, so OK there. This is a stationary set up with no rewiring. I have a 6 wire firewire out of the mac mini, so it does carry power. Typically, I first turn on the hard drives, then the mac, then plug in the wallwart power to the MBox, even though it could draw power from the firewire. This worked OK for over a year before the problem.
  6. ahavill

    ahavill Guest

    Oh I see, the MBox has no power switch... so once the HDs power up, it powers up via FW, right? (Before the computer.) I don't think you should use the wall wart unless you have to, and I wouldn't attach it after the rest of the system is running. Its a guess, but maybe if its getting power from the FW cable AND the ps, its too much. I know you said you've used it like that for a while, but I think the ext ps for the MBox is provided for when you don't have 6-pin pwrd FW. Same goes for the HDs imo: don't use the wall wart unless you have to, your mini is plugged into the wall so you've got solid power on the 6-pin FW.
    Also in the orig post you said that "Digi fixed the box but (you) still have the same problem." You mean it stopped working, you sent it to Digi, they sent it back, & it still didnt work? or did it work then die again?

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