Zapping firewire ports

Discussion in 'Amateur Video Production' started by Johan Stäck, Feb 28, 2007.

  1. Johan Stäck

    Johan Stäck Guest

    Unfortunately, I have "zapped" the firewire ports on several camcorders.
    (+ one firewire disk)
    One (TRV900) was repaired, the others are just written off (still
    working for recording though)

    I *think* I understand why this happened.
    It was because the PC was connected to an ungrounded 220v outlet.
    See http://www.epanorama.net/documents/pc/ungrounded_pc.html

    Since the PC ground can be floating at 110v it is easy to understand
    that this could damage a firewire peripheral.

    After I had a grounded outlet installed, I have not had another
    incident, but I am still worried.

    Anyone with experiences and/or ideas on the subject of zapped firewire
    ports on camcorders?
    Is this a common problem?

    /Johan Stäck
    Skellefteå
    Sweden
     
    Johan Stäck, Feb 28, 2007
    #1
    1. Advertisements

  2. Johan Stäck

    Gene Guest

    If you think that you may have a grounding problem, and want
    to go to the effort - there is one way that is probably better than
    all others. Back in the 1960's we always installed what we called
    a "true" ground to all mainframe computers. In the case of PCs, it
    would be a copper wire attached to the case, then run to an 8 foot
    long grounding rod. If you have noise, etc. - this can be a BIG help.
    It is critical that the rod be in damp soil to make a good contact
    with the earth, very dry soil will not work. You are grounding your
    PC case directly to the earth, for a perfect ground. The thing that
    I never could understand was "what is the earth grounded to"? :)

    Gene
     
    Gene, Feb 28, 2007
    #2
    1. Advertisements

  3. Some vendors (Sony, Apple, etc.) now caution against
    "hot-plugging" Firewire cables because there have been
    so many complaints about fried ports.
     
    Richard Crowley, Feb 28, 2007
    #3
  4. Johan Stäck

    nappy Guest

    yes. I believe it is caused by a differential between the two devices'
    grounds. However, some firewire ports have better protection at the inputs
    than others. That said, we had a mac years ago that fried three times. In
    different installations. with well grounded setups.

    Have not yet fried a camera port.
     
    nappy, Feb 28, 2007
    #4
  5. I've been lurking in various video groups for a while, & this seems to
    be a common problem when powering both the camera & computer off the
    mains. Reports have been made of both ends being fried, especially in
    situations where maintenance or care of cables may be suspect.

    The recommended connection sequence is to disconnect the camera from the
    mains, connect the firewire cable, then reconnect the camera mains power.

    As I understand it the problem is caused by the protective earth on the
    firewire connector not always connecting before the signal cables,
    either due to a bad wire, or a bad connection inside the plug/ socket
    assembly, giving a short pulse of up to 200 volts at the input & output
    pins on the firewire connection, if either or both pieces of equipment
    aren't grounded properly. Interestingly. I've never heard of a similar
    problem on USB....

    Tciao for Now!

    John.
     
    John Williamson, Feb 28, 2007
    #5
  6. Johan Stäck

    Gene Guest

    That makes a lot of sense.

    I have found the tiny "4 pin" connectors to be iffy at
    best. On at least two of my Sony camcorders
    it takes a LOT of force to cause the 4 pin firewire
    cable connector to make a good connection. A sloppy
    built 4 pin firewire plug could easily short out if not
    FIRMLY seated. They are a crimped plug, and the seam
    is too close to the pins - bad design. As a general rule, I
    NEVER power up , or power down the PC when a camcorder
    it attached via firewire - whether the camcorder
    has power or not. I have never fried a camcorder firewire
    port, but can see where it could be very easy to do...

    Gene
     
    Gene, Feb 28, 2007
    #6
  7. On 2/28/2007, Gene posted this:
    [...]
    I hope you're kidding with that question, but in case you're not, the
    earth *is* ground.

    That's precisely why the British call it "earth" - and why on this side
    of the Atlantic we call it "ground".

    In the old days, telegraphs used one wire for one side of the circuit
    and the earth for the other.

    Now we use it as a reference to prevent - and sometimes cause - shock
    and other problems.

    [...]
     
    Gene E. Bloch, Feb 28, 2007
    #7
  8. Johan Stäck

    Gene Guest

    Yeah, just funnin'

    Deep thought though :)

    Gene





     
    Gene, Mar 1, 2007
    #8
  9. OK, looks like your humor is grounded in reality :)

     
    Gene E. Bloch, Mar 1, 2007
    #9
  10. Johan Stäck

    Johan Stäck Guest

    nappy skrev:
    am still worried.
    Problem as I see it is that the camcorder is not grounded at all
    (through the power supply that is).
    The power supply uses un ungrounded connector, and the camcorder is fed
    with low-voltage DC.

    Someone in a swedish group commented that the camcorder is just like a
    bird sitting on a high-voltage power line.
    Since the bird is ungrounded it can be hurt.
    The same would go for a camcorder connected to an ungrounded PC.

    However, I have fried a number of firewire ports in camcorders, and I
    need to understand how to prevent it happening again.

    True as someone said, that this problem seems not to happen with USB!


    But evidently one should
    -keep everything grounded (as far as it can be done)
    -avoid hot-swapping

    /Johan
     
    Johan Stäck, Mar 1, 2007
    #10
  11. Johan Stäck

    Gene Guest

    NEVER power ON or OFF the PC if the camcorder is connected
    via firewire - even if the camcorder is turned OFF.

    Gene
     
    Gene, Mar 1, 2007
    #11
  12. Johan Stäck

    Steve King Guest

    Wait a minute! I can't hot swap, AND I can't turn on the PC if a firewire
    connection is plugged it? I think that leaves no choices? What's up?

    Steve King
     
    Steve King, Mar 1, 2007
    #12
  13. Johan Stäck

    nappy Guest

    hmm.. overkill. While I did have firewire ports die on a MAc. I have
    numerous FW cameras, decks,DVD recorders and audio interfaces and I have
    never had a problem hot plugging any of those with a number of PCs for about
    ten years now.
     
    nappy, Mar 1, 2007
    #13
  14. "Gene" wrote ...
    Sony and Apple recommend the opposite.
    That you ONLY connect a Firewire/iLink cable
    when powered down.
     
    Richard Crowley, Mar 1, 2007
    #14
  15. Johan Stäck

    Gene Guest

    I have seen that too, but I'm only suggesting what
    has worked for me for a LOT of cycles and with five
    or so different Sony and Cannon camcorders.

    Here is what I do, and have never had a problem:

    1. Power up the PC with the firewire cable plugged into the
    PCI card, and the other end NOT plugged into anything.
    2. With the camcorder powered down, plug the firewire cable
    FIRMLY into the camcorder.
    3. Power on the camcorder, the PC should see it.
    4. BEFORE powering down the PC, power off the camcorder &
    remove the firewire cable from the camcorder.

    The above procedure may not work for every PC and camcorder
    combination - so I would go with the advice of the camcorder
    manufacturer if you are concerned. My reasoning for the above
    procedure is that I feel the surge of powering up & down the
    PC is more likely to zap my camcorder than attempting a hot plug
    into a camcorder that is turned off. (NEVER do this if the camcorder
    is powered-up in any way.)

    The above has always worked for me. It may, or may not, work
    for everyone - YMMV.

    Gene
     
    Gene, Mar 1, 2007
    #15
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.