ASUS P4C800-E Deluxe: Warning, onboard Firewire may have fried my components, details inside...

Discussion in 'Asus' started by Z Man, Nov 29, 2003.

  1. Z Man

    Z Man Guest

    Here's my story, you draw your own conclusion. I just installed this
    motherboard about a week ago. One of its selling points was onboard
    Firewire. I have more Firewire peripherals than most PC users, including an
    80GB hard drive, DVDRAM/-R, Canon ZR10 mini-DV cam, and Apple 30GB Ipod. All
    these peripherals are external, and I use them on a variety of computers in
    my home and office. After installing my new motherboard, I could not get
    these peripherals working correctly. The DVD-RAM never worked with this mb.
    the Canon worked all the time. The external 80GB hard drive worked for
    several days, then stopped working. The Ipod worked for a day or two, then
    stopped working.

    Here's what I did: I took my Ipod to a local Apple store, and they confirmed
    that it was dead. They replaced it under the warranty. The external hard
    drive is in a Firewire/USB2 case. It now works with USB2. The DVD-RAM case
    is Firewire only, so I will have to discard it (since the problem, I have
    tried it on two other computers, both of which previously used this
    peripheral without issues). I have since disabled onboard Firewire and
    installed a Firewire card (with Lucent chipset, I have lots of computers and
    spare parts). My new Ipod now appears to work correctly, and my mini DV cam
    works, as it did before. I am theorizing that the camcorder never suffered
    because it does probably does NOT get its power from the port; instead, it
    gets plugged into an a/c outlet. If that assumption is correct, it is the
    only peripheral that was never at risk. The DVDRAM and hard drive also use
    external power, but their six pin Firewire cables carry power, as well.

    So, what do you think? Could it be that the power output from the onboard
    Firewire port is too high, and ruined my equipment? Any other theories or
    ideas would be welcomed. Post them right here so we can all join in. As the
    saying goes, 'a word to the wise is sufficient'.
     
    Z Man, Nov 29, 2003
    #1
    1. Advertisements

  2. Z Man

    Z Man Guest

    I have disabled onboard Firewire, and am using a PCI Firewire card, so I
    feel that I am no longer at risk of damage to my peripherals. I have used my
    Ipod a few times with the PCI Firewire card and experienced no issues. The
    motherboard itself is first-rate. I have used/built lots of computers, and
    this one could easily be the best...except for the Firewire issue.
     
    Z Man, Nov 29, 2003
    #2
    1. Advertisements

  3. Z Man

    steve Guest

    I was about to get this board, but reading this post and another above
    I cannot take a chance with firewire.
    I cannot risk my peripherals.
    Are you sure that camcorder is not at risk?

    Firewire must work. Are you guys sure about what you are observing?
    Maybe it is just some probability that your board is like that (if it
    really is the case that is) and this happens with other boards you
    think?
     
    steve, Nov 29, 2003
    #3
  4. Z Man

    Paul Guest

    One part of your story I'm having trouble with is the death of the Ipod.
    I thought the Ipod was battery powered, and recharged itself from the
    cable. In the stuff I read about below, I cannot think of a reason for
    the Ipod to die, but some other peripheral powering cases can certainly
    result in a dead Firewire interface.

    To properly answer your question would require a copy of IEEE1394-1995
    specification (or any followups the IEEE published). That is a spec you
    can buy from the IEEE, so it is unlikely you'll find a copy floating
    around on the net. There is also www.1394ta.com, but like any good
    trade association, there is no free lunch there either.

    The only useful free information I can find is this Texas Instruments
    application note:

    http://focus.ti.com/lit/an/slla011/slla011.pdf (Galvanic Isolation IEEE1394)

    It states some of the power, grounding, and signal isolation issues with
    1394. To do a Firewire interface properly, you need:

    * Shield termination (DC isolation)
    * Cable power isolation (floating power source)
    * Signal isolation (DC isolation between systems, between MAC and PHY)

    In the case of shield termination, the idea is to avoid "ground loops"
    in the grounds being used by the various Firewire devices. The TI document
    says to use a capacitor and high value resistor to join the shield of the
    cable to ground on the local equipment. The capacitor makes an "AC ground",
    so AC currents are grounded, but there is no DC path for ground potential
    differences to cause current to flow. The high value resistor doesn't pass
    any significant current, and is used to "bleed" ESD. In the case of my
    Antec computer case, this principle is violated by the joining of the
    USB ground to the Firewire ground, on the case front connector. You could
    have a similar violation buried somewhere in your system.

    The second issue is cable power isolation. The VP and VG are supposed to
    be powered by a transformer isolated power supply. The PC power supply
    joins the green "safety ground" to logic ground, so a separate DC-DC
    converter would be required to meet the 1394 requirement. I cannot
    imagine any Taiwanese manufacturer wasting their money on something
    like this. That means each PC has already compromised that requirement.
    (That means you should be especially careful doing Firewire networking
    between two PCs !!! If you use six pin cables, there had better be
    diodes on the +12V coming from the motherboard...)

    In terms of the voltage and current level, the TI doc says the VP/VG
    power supply can be 40 volts at up to 1.5 amps. An Apple computer happens
    to use 25 volts or so, to power Firewire devices. Every IBM PC will be using
    the +12V (the same supply used on the processor Vcore cct). So, the PC
    doesn't have too high a power output. To see an example of how powering
    is handled in a sample Firewire implementation, look at the schematic
    on page 10 in this document:

    http://www-s.ti.com/sc/psheets/slla153/slla153.pdf

    In the schematic, the Firewire design converts VP/VG
    using the LM2574HVM-3.3, which is a high voltage rated DC-DC stepdown
    converter, for converting up to 40VDC to +3.3 for local logic. So, that
    shows that a responsible peripheral design, if it wants to extract power
    to run the Firewire interface at all times, would use a high voltage
    part to do power conversion, and wouldn't burn out.

    http://www.national.com/search/search.cgi/main?keywords=LM2574

    While looking at that schematic page, you can see some other safety
    features. There is a diode and fuse, where the design connects to VP.
    This allows current to only flow one way, and that same diode and fuse
    should be used on Firewire equipped motherboards. If the diode is not
    present, nasty things will happen when a +25V computer connects to a
    +12V computer.

    Looking at the Firewire connectors, you can also see the use of capacitors
    for the isolation functions.

    The third thing the TI document mentions is isolating the MAC to PHY
    interface. Capacitive coupling is supposed to be used to allow signals
    to be passed from chip to chip. Since many chips are now integrating
    the MAC and PHY function, this feature would be hard to implement, at
    least to handle any reasonable voltage difference.

    So, given all the compromises that appear to be at hand, what can
    you do ? I would suggest the following:

    1) Power up the peripheral before connecting it to the computer.
    The idea here, is to allow the peripheral to satisfy its power
    needs locally, with all circuitry ready to go, before firing up
    the computer. If you want to leave the Firewire cable in place,
    then power the peripheral first, following by pushing the button
    on the front of your PC case. If you put your computer to sleep,
    leave the Firewire device power switch in the ON position.
    Otherwise, power the Firewire device down and then disconnect
    the cable, before the next time your PC is awakened.

    2) For extra protection in cases where you are uncertain about
    the isolation of the power source, only use 4 pin connectors, not
    6 pin connectors. Get a 6 pin to 4 pin conversion cable, as this
    will stop the VP/VG cable power from flowing. Then, the powering
    situation when connecting a single peripheral to a PC will be a
    lot easier to understand. Your Ipod will no longer be recharging
    from the cable, but it might not die either.

    3) For devices that are powered from the wall, try to plug all the
    devices into the same power strip. Use a quality strip that doesn't
    make questionable contact with the green safety ground.

    Another way for silicon devices to die, happens when you "hot swap"
    a device, and the signal contacts are the first to touch the foreign
    system. Then, whatever voltage difference exists between devices gets
    applied directly to the pins, and that can cause the device to die.
    In lower speed interfaces, clamp diodes can be used to limit this
    effect. Since Firewire runs at 400Mbs, clamp diodes would degrade the
    signal quality, so they cannot be used. In any case, this is not
    an issue, as the Firewire connector design is such that the cable
    shield touches first, before anything else does.

    So far, I haven't been able to find any more useful tech info on
    Firewire, so these are just the things I'll be trying when I get
    my Firewire enclosures (soon). As I've read about Macintosh users
    burning out Firewire interfaces, I think it pays to be extra
    careful, especially when using expensive devices like cameras.
    I hope someone has better luck finding some good info on Firewire
    than I've had.

    My initial impression is the Firewire industry is pretty lax.
    I bet you won't see any motherboard manufacturers joining the 1394TA.

    If these device deaths are happening after using the computer case
    front panel connectors, be aware that many cases have miswired
    connectors on the front. If using a connector on the front of the
    case, verify the pinout with an ohmmeter, before destroying any
    expensive peripherals.

    HTH,
    Paul
     
    Paul, Nov 30, 2003
    #4
  5. Z Man

    Mark Guest

    Mark, Nov 30, 2003
    #5
  6. Hi,

    I have kind of same problem. Here is what I have done so far.

    Connect my DV cam (Sony) to FireWire port to capture some video. No results.
    Try the other port. no result either. I always got a message: no device
    detect or an other device is using....

    Send a message to ASUS about what seems to be a problem (I am still waiting
    for an answer 2 weeks later...).

    Post a message here 2 weeks ago. No answer...

    Bought a FireWire cars (PCI) on the suggestion of members of the Ulead MSP
    newsgroup. Install it. Try to transfert. No results.

    So, I take back my old computer (gave it to my girlfriend). I am sure it
    was working OK. And it was not used at here place. Connect my DV to it: same
    thing happended. Got a message that another device was using the port or
    that there is no device.

    To my, there is only one explanation: the ASUS board fried something in my
    DV cam.

    I will test that this week on a computer that is working for the transfert
    of video by a FireWire card to see if I'm right.

    What do you think?

    Thanks

    Bernard
     
    Bernard Mataigne, Dec 1, 2003
    #6
  7. Z Man

    Mark Guest

    Bernard,
    How do you know the pc you intend to use to test your cam is OK and
    has the correct drivers installed? When I first bought a DV I had
    many headaches trying to get it to communicate with the pc (running
    W98se with added pci firewire card). The manual for the cam (JVC) was
    no help at all. I finally worked it out by just continually chipping
    away at the problem til it worked.

    In any case I'd sure check those links & using the wiring diagrams
    insure that the port is correctly wired--before trying to hook up any
    more devices to it. Your cam probably has a tiny chip inside that is
    only for firewire connectivity. If the port is miswired & it fries
    that chip, the cam may work perfectly fine in every other way EXCEPT
    firewire transfer. And I bet the cost to repair would exceed the cost
    to replace.
     
    Mark, Dec 1, 2003
    #7
  8. Hi Mark,

    I know the people who use the computer for their transfert. I spoke with
    that person (he is a friend of mine, head of the computer department of a
    school district). They use Windows systems (XP) with DV Cam (Sony) and they
    transfert regularly video.

    So I suppose that if my DV Cam don't transfert, it will be my cam that is
    broken. I bring my firewire cable too... By the way, my cam is working OK
    except for the transfert. So, as you say, it seems to be only the firewire
    aspect that is broken.

    There is something else apart from the fact that I got the message "...
    device is not ready" or "there is another device...", that I forgot to say.
    Now, when I plug my DV cam on the Asus firewire, my cam flash "DV in" (cam
    is in VCR mode), as if the cam was receiving a signal from the card!
    Strange. Never saw that before.

    So, I will know wednesday if the cam is fried or not...

    Bye

    Bernard
     
    Bernard Mataigne, Dec 2, 2003
    #8
  9. Z Man

    Paul Guest

    I got my ADS Pyro1394 (ADI-800) external enclosure yesterday and have
    had time for a quick test. I had no problems connecting the enclosure
    to my computer, except for one combination. If the computer is still
    operating and I kill the power switch on the enclosure, I can hear a
    strange sound coming from the power converter on the bridge board inside
    the enclosure. Also, the drive activity light on the front of the case
    is partially lit.

    It seems like the VP/VG power on the Firewire cable is somehow causing
    the bridge board to be partially working. Or, at least the switching
    converter on the bridge board (probably makes a local +3.3V for the
    Oxford 911 chip) is still running. Since the drive activity light is
    half lit, that means the circuit is under some kind of stress. This
    could be due to some parasitic diode path that is grounding the supply.
    What I'm seeing and hearing doesn't suggest a happy circuit.

    Now I've got to dig up some 6 to 4 pin cables and adapters, so the VP/VG
    from the computer cannot make it to the enclosures. When two of the
    enclosures are connected to one another, but not to the computer,
    everything is fine. (One powered enclosure will not try to power
    the second enclosure.)

    HTH,
    Paul
     
    Paul, Dec 10, 2003
    #9
  10. Power issues aside for a moment.....Did you eventually resolve your data
    integrity problems with the onboard firewire? I believe you concluded that
    it was unreliable in an earlier post in another thread.
     
    Derek Hawkins, Dec 11, 2003
    #10
    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.