here is how firewire ports fail

Archived from groups: rec.audio.pro (More info?)

this is a copy in its entirity from what M-Audio sent me about firewire
failures

> ³FireWire Port Failures in Host Computers and Peripheral Devices²
>
>  
>
> a White Paper
>
>  
>
> by James Wiebe, CEO
>
> WiebeTech LLC
>
> jameswiebe@wiebetech.com
>
> http://www.wiebetech.com
>
> © 2003 All Rights Reserved
>
>  
>
> This paper may be reproduced, but only in its entirety, and only if credit is
> given to the author and linkage provided to the WiebeTech website.
>
>  
>
> DISCLAIMER
>
>  
>
> The cause of FireWire port failures is extremely complex and this White Paper
> cannot embody all possible failure scenarios or solutions to the problems. 
> The author specifically disclaims any fitness for use of the information
> contained within this white paper. 
>
>  
>
> Port failures are often discussed but remain a relatively infrequent problem,
> especially if the FireWire storage device and the host computer are properly
> designed. 
>
>  
>
> Statistics for total failures of FireWire ports is not known.  Judging from
> the number of posts on Apple¹s website:
>
>  
>
> http://discussions.info.apple.com/ [...] 2@.ef0a4bc
>
>  
>
> as well as posts on the website:
>
>  
>
> http://www.macintouch.com/firewirereader02.html
>
>  
>
> this topic is assumed to be of interest to many readers.
>
>  
>
> The author seeks input from anyone who may have additional information which
> can shed light on the subject of this White Paper.  Questions concerning
> particular types of equipment should be directed to the respective
> manufacturer.
>
>  
>
> 1.         INTRODUCTION
>
>  
>
> FireWire allows users to connect storage devices and other peripherals to
> host computers, giving unparalled flexibility in data capture, storage,
> transportation, and backup capabilities.  FireWire allows devices to be hot
> swapped from one computer to another.  Hot swapping allows FireWire storage
> devices (as well as other peripherals, such as video cameras) to be
> physically attached to a FireWire port, automatically mounted on the desktop,
> accessed, and then unmounted / disconnected at the command of the user.
>
>  
>
> The resulting ease of use has caused FireWire technology to be widely
> accepted by millions of users.  FireWire is directly supported by a variety
> of operating systems, including Windows 98SE, ME, 2K, XP and Mac OS9.1, 9.2
> and OSX.  Linux also is capable of supporting FireWire, although the process
> of setting up first use on that platform may be a little more difficult. 
>
>  
>
> Users have reported failures of FireWire ports on host computers after
> attaching FireWire devices to those ports.  This can be quite unsettling to
> the user, since the failure of the FireWire port can be crippling to the
> utilization of the computer.  For instance, it may become impossible to
> create backups or attach FireWire peripherals to the computer after failure
> of the port.
>
>  
>
> The purpose of this report is to provide background and technical analysis of
> the failure of the ports.  In conclusion, methodologies will be suggested
> which may substantially reduce the incidence of damage to host ports.
>
>  
>
> 2.         BACKGROUND INFORMATION ON FIREWIRE OPERATION
>
>  
>
> In order to understand the issue, it is necessary to understand just a little
> bit of how FireWire operates.
>
>  
>
> FireWire allows the attachment of external devices to host computers through
> a cable which is composed of the following wiring components:
>
>  
> € Serial Data Pairs, of which there are two, giving a total of 4 wires.
> € Power, which is generally somewhere between 8 to 24 volts DC.
> € Ground, which is a lead that provides a current return for the Power
> line.
> € Shield, which helps prevent the emission of Radio Frequency
> Interference from the FireWire cable.
>
>  
>
> The Power and Ground lines must be present to allow FireWire devices to be
> bus powered.  For instance, portable FireWire drives usually run off of bus
> power, meaning that they will function when attached to a powered FireWire
> host.  Other types of FireWire devices, such as Desktop FireWire drives,
> usually (but not always) require a separate power supply.  As a result, they
> do not utilize any power from the Power / Ground pair provided by the host
> FireWire port.  They obtain their power from an independent power supply.
>
>  
>
> Manufacturers are not required to provide Power and Ground within the
> FireWire host.  Two different types of commonly used FireWire connectors have
> been defined for FireWire 400 usage.  One of these types is the more common
> six pin connector, while the other type is a physically smaller connector
> which omits Power and Ground.  Obviously, bus powered FireWire devices will
> not work when attached to a FireWire host which does not provide bus power. 
>
>  
>
> Apple computers generally include all of these lines in their FireWire ports,
> while certain PC computers with FireWire capability (such as the Inspiron
> 8200 from Dell or various Sony Vaio laptops) omit the Power and Ground
> lines.  The omission of these lines prevents the use of ³bus-powered² storage
> devices.  This is why portable FireWire drives won¹t work when attached
> directly to PC laptop computers, such as the Dell or Sony models.  No power
> is present on the port.
>
>  
>
> 3.         FIREWIRE FAILURE SCENARIO
>
>  
>
> A typical failure scenario is as follows:  The user attaches a FireWire
> storage device to the computer.  The user expects the device to mount on the
> desktop, but this does not occur.  Repeated attempts to mount the storage
> device (usually by connecting and disconnecting the FireWire cable) produce
> the same results.  Ultimately, the user attempts to mount other FireWire
> devices on the same port without success, and consequently verifies that the
> port is no longer functional.  Various attempts to resolve the situation may
> be attempted, all without success.  This may include machine rebooting,
> Parameter RAM resetting, power disconnection for extended periods of time,
> etc.
>
>  
>
> It¹s worth noting that the host FireWire port may be on the motherboard (as
> is the case for most Apple computers) or it may be on a PCI FireWire host
> adapter card.  The result is the same; the particular port no longer works. 
> The port may still be capable of supplying power to the attached FireWire
> device, but the device is no longer seen on the desktop or in the various
> disk management utilities.
>
>  
>
> The failure of the host¹s FireWire port can produce a very bad day for the
> user.  The knowledge of possible damage (and consequential repair cost /
> hassle) to the computer is compounded by the frustrating inability to mount
> and use external storage devices.
>
>  
>
> 4.         FAILURE CAUSES
>
>  
>
> 4.1       LOSS OF POWER FROM THE PORT
>
>  
>
> What went wrong to cause the failure of the FireWire port?
>
>  
>
> In order to answer the question, let¹s consider the two main functional
> components of the FireWire interface:  the Data lines and the Power lines.  A
> failure mode is the loss of Power through the FireWire port.  A second
> failure mode (which the author believes to be far more likely) is a failure
> of the port¹s ability to supply Data to the FireWire device. 
>
>  
>
> These failure modes cause us to consider:  why would a port lose the ability
> to supply either Power or Data? 
>
>  
>
> In the testing and development of FireWire storage devices, we (WiebeTech)
> have accidentally shorted the FireWire Power / ground lines together many
> times.  This can cause a variety of results:  the immediate shutdown of the
> entire computer system; the shutdown of an individual port; etc.  Apple
> documents that their ports are provided with triple redundant fusing for
> protection against power shorts such as the one just described.  The
> applicable document can be accessed at the following URL, showing FireWire
> specifications on all Apple computers:
>
>  
>
> http://docs.info.apple.com/article.html?artnum=58207
>
>  
>
> The Apple document states:
>
>  
>
> ³Power safety -- The FireWire bus has three self-resetting fuses. If your
> device unexpectedly shuts down, it may be due to an overloaded fuse. If this
> occurs, disconnect the device immediately.²
>
>  
>
> Field experience shows that the power side of the FireWire host port rarely
> fails.  Fuse protection appears to adequately protect the port against most
> problems.
>
>  
>
> 4.2       LOSS OF DATA TRANSMISSION FROM THE PORT
>
>  
>
> The second failure mode is the failure of the port¹s ability to supply Data
> to the FireWire device.  As previously stated, the author believes this to be
> the most common failure mode when FireWire ports fail.
>
>  
>
> FireWire ports within most peripherals are composed of two devices:  the
> FireWire bridge, which connects to the drive and to the FireWire ³PHY², and
> the ³PHY², which connects from the FireWire cable to the FireWire bridge. 
> The PHY receives nearly no mention in most discussion of FireWire devices,
> but it is actually responsible for the electrical connection to the FireWire
> cable, and ultimately, the host device.  The host devices¹ FireWire
> connection is very similar, using a PHY to connect the motherboard
> electronics to the FireWire port.
>
>  
>
> The author has direct experience observing the failure of FireWire ports in
> peripheral devices under developmental test conditions.  This experience
> shows that most port failures occur within the PHY, not in the FireWire
> bridge, and not in the power supply portion of the port. 
>
>  
>
> Post mortem examination of the decapped (plastic removed) failed PHY shows
> gross failure of the circuitry which attaches the Data lines.  After removing
> the plastic package from the integrated circuit, an examination of the
> integrated circuit under a microscope shows clear evidence of electrical
> damage to the part.
>
>  
>
> In other words, something zapped the PHY.  How is this possible?
>
>  
>
> It really wasn¹t supposed to be possible for the PHY to fail.  However, there
> are at many different events which can cause the PHY to fail.  Some of these
> are very easy to understand, while others are a bit more difficult to
> understand.
>
>  
>
> 4.2.1    FAILURE BY ELECTROSTATIC DISCHARGE (ESD)
>
>  
>
> The failure scenario is as follows:  The user inserts a FireWire cable into
> the host.  The user then picks up the other end to attach to the FireWire
> device, and inadvertently discharges ESD through one of the Data lines to the
> host port.  Part destruction occurs.
>
>  
>
> In the real world, this does not (or at least should not) happen frequently. 
> The user is far more likely to discharge through the Shield of the FireWire
> cable, which will dissipate the discharge directly to a ground within the
> host computer, without damaging internal circuitry. 
>
>  
>
> 4.2.2    PORT FAILURE BY BAD CABLE OR BAD INSERTION
>
>  
>
> This failure scenario actually has three sub-scenarios, each of which will be
> described in turn.
>
>  
>
> 4.2.2.1 PORT FAILURE BY REVERSE INSERTION
>
>  
>
> In this scenario, the user inserts the cable with the connector twisted 180
> degrees.  An examination of the FireWire six pin ports suggests that this is
> not possible, but it has actually been done many times.  It is more likely to
> happen when the port is worn, or when the port easily ³spreads² when reverse
> inserted.  Some FireWire ports are built with the metal seam at the narrow
> end of the port, making it much easier to reverse insert the cable.  The
> resulting (errant) electrical connections cause Power lines to be directly
> connected to Data lines.  This invariably fries the PHY attached to that
> port.
>
>  
>
> 4.2.2.2 PORT FAILURE BY BAD CABLE
>
>  
>
> Any internal failure of a FireWire cable which results in Power being shorted
> to a Data line within the cable usually will result in the failure of the
> port to which it is attached.
>
>  
>
> The author was directly told of a typical experience at a major computer
> company.  An employee observed that his FireWire drive would not mount. 
> Suspecting trouble and wanting to verify it, the employee tested the device
> on three more computers.  The device wouldn¹t mount on any of the four
> computers.  The ultimate cause of the problem was a bad cable which fried
> four host ports on the four computers.  The FireWire drive was not at fault. 
> The author assumes that each of the four PHYs was destroyed.
>
>  
>
> 4.2.2.3 PORT FAILURE BY FIREWIRE CABLE TWISTING
>
>  
>
> In this scenario, the user correctly attaches the FireWire cable to the
> computer and the storage device.  A rotational twisting force is applied to
> either connector at either end of the cable, in relationship to the port in
> which it is inserted.  As the connectors are pushed out of position by the
> rotational torque, a short occurs between the Data lines and a Power line,
> resulting in port failure. 
>
>  
>
> 4.2.3    PORT FAILURE BY INDUCED UNDER/OVER VOLTAGE CONDITION
>
>  
>
> This is the scenario which is most difficult to understand.  Essentially, the
> PHY creates or experiences a damaging voltage on one of the Data lines.  This
> error condition is very transient in nature and is caused at startup time of
> bus powered FireWire devices by a bump or droop on a power supply within the
> FireWire device.  The bump or droop is understood through a detailed analysis
> of the actual circuit of the FireWire device, cable, and host port as current
> starts to flow through the Power lines at startup time.  Equivalent circuitry
> must be considered:  IE, inductance within power lines, etc.  (The
> engineering analysis is far beyond the scope of this paper.)
>
>  
>
> As a result, the external FireWire device may briefly experience or transmit
> a damaging voltage to the host computer¹s FireWire port, resulting in the
> destruction of the port.  
>
>  
>
> This failure mode is the one most likely to have created the impression that
> bus powered devices cause FireWire host port failures.
>
>  
>
> 5.         PREVENTING FIREWIRE PORT FAILURE
>
>  
>
> 5.1              OBVIOUS PREVENTATIVES
>
>  
>
> Certain preventive measures seem obvious:
>
>  
> € Always use high quality FireWire cables.
> € If a cable is worn out, replace it immediately.  (Cables used at
> WiebeTech are used heavily throughout every business day; they are
> generally replaced every month, if not more frequently.)
> € Never insert a cable backwards into a port.  If this happens before
> the cable is also attached to the host (or to the peripheral device), get
> the port repaired prior to further use of the device (or host).  Discard
> the cable and use a new one.
> € If a device does not mount, attempt mounting it with a new cable on
> the same port.  Always suspect the cable before suspecting a failure of
> the device.  Try powering the host down; rebooting; etc.  Port failures on
> machines tend to follow the cable.
>
>  
>
> 5.2              PREVENTING PORT FAILURE WHEN USING BUS POWERED DEVICES
>
>  
>
> What follows is three different methods for preventing port failure when
> using bus powered devices.  All require support from the FireWire peripheral
> manufacture and from the host computer.  Other methods are also available ­
> this is not meant to be an exhaustive list.
>
>  
>
> 5.2.1        ESD AND OVER/UNDER VOLTAGE
>
>  
>
> This technique requires installation of protective devices on the FireWire
> port on the host computer.  The protection is installed on the motherboard
> close to the PHY device, with direct connections to the Data lines.  An
> excellent example of how Apple has implemented this technique in certain
> reworked motherboards is found at the following URL:
>
>  
>
> http://www.medicalmac.com/mac98e.html
>
>  
>
> Through proper implementation of this technique, the FireWire port is
> protected against Electro Static Discharge (ESD) as well as problems caused
> by bus powered devices. 
>
>  
>
> The author believes that Apple has been implementing the technique in all
> recent and currently shipping Apple computers.  Suppression of ESD and
> over/under voltage is a primary method of reducing or eliminating port
> failure and must be implemented on the host computer to be effective.
>
>  
>
> 5.2.2    VOLTAGE TRANSIENT SUPPRESSION CIRCUITRY ON BUS POWERED DEVICES
>
>  
>
> WiebeTech has implemented a proprietary technique which prevents transients
> at power on time from being transmitted to the host computer via the Data
> lines.  This resolves issues related to use of bus powered devices.  This
> technique has been used with excellent results in WiebeTech¹s bus powered
> FireWire DriveDock devices, which are capable of bus powering 3.5 inch IDE
> hard drives. 
>
>  
>
> 5.2.3        THE USE OF A POWER SWITCH IN BUS POWERED DEVICES.
>
>  
>
> WiebeTech recommends the use of power switches in bus powered FireWire
> devices.  This prevents the PHY within the FireWire device from transmitting
> voltage transients through the FireWire cable to the PHY on the motherboard
> of the host computer.  Simply put, the FireWire device is not powered up
> until all connections have been made and voltages have had a chance to
> stabilize.  This technique is used on WiebeTech¹s portable drives, including
> the MicroGB+; MicroGB+Combo; and 3.5 inch bus powered UltraGB.
>
>  
>
> 5.2.4        CURRENT LIMITING OF POWER ON TRANSIENTS
>
>  
>
> WiebeTech has also implemented a technique which allows the power supply of
> the FireWire device to ³soft start² while the device is still in the off
> position.  This is implemented in WiebeTech¹s UltraGB 3.5 inch bus powered
> drive.  The UltraGB has a three position switch:  Bus Power ­ Off ­AC Power. 
> When the Off position is selected AND when the device is attached to a host
> through a FireWire cable, the internal power supply ramps up to voltage
> through a current limiting circuit into a power storage circuit.  This
> provides important benefits:  a substantial amount of power may be ³saved
> up², helping large drives to spin up successfully; and power on transients
> are filtered through the current limiter, substantially reducing bumps and
> droops in the power supply.
>
>  
>
> 5.3       OTHER METHODS OF RESOLVING HOST PORT FAILURES
>
>  
>
> 5.3.1        REPAIR THE MACHINE
>
> If the user has a computer under warranty, it is likely that the manufacturer
> will repair the damaged port without charge of any kind.  It may be
> worthwhile checking with the manufacturer, even if the computer is out of
> warranty.
>
>  
>
> 5.3.2    ADD AN INEXPENSIVE FIREWIRE HOST CARD
>
>  
>
> If the machine is out of warranty and has available PCI slots, the simplest
> way to repair the computer is to add a FireWire PCI card.  They are
> inexpensive and very easy to install.  Most operating systems do not require
> the installation of any additional software drives to support FireWire usage
> through a PCI card.
>
>  
>
> 6.                  CONCLUSIONS
>
>  
>
> Most of the failure modes of FireWire ports are believed to be caused by low
> quality or worn out FireWire cables, operator error during device and cable
> insertion, inadequate PHY port protection, and improper design of external
> FireWire devices which causes voltage surges to the host port.
>
>  
>
> 6.1       CABLE PREVENTATIVES
>
>  
> € Users are encouraged to use high quality FireWire cables.
> € Users are encouraged to replace worn out FireWire cables.
> € Never plug a FireWire cable in backwards (although it seems
> impossible; it¹s been done many times.)
> € Don¹t apply twisting torque to cables that are inserted into sockets.
> € If a device doesn¹t mount, do not test the cable on another machine.
>
>  
>
> 6.2              HOST PORTS
>
>  
> € Older computers may not have FireWire port protection built into
> them.  This appears to place them at higher risk of failure.
> € Recently manufactured computers are likely to have enhanced port
> protection.
> € If your port fails while the computer is within warranty, you won¹t
> have any problems getting it repaired.
> € If your port fails while the computer is out of warranty, an
> inexpensive solution is to use a low cost PCI FireWire host card.  
> (assuming you have open slots).
>
>  
>
> 6.3       FIREWIRE PERIPHERALS
>
>  
> € FireWire Peripherals should have a transient limiting circuitry on the
> Data lines at power up time, in order to prevent transients from causing
> damage to the host¹s PHY.
> € An alternative method is to use FireWire devices that are turned on
> via switch after attachment to the FireWire cable.
> € Another method is to use FireWire peripherals with built in inrush
> current limiting on the Power lines.
> € Always follow the attachment and power up recommendations of your
> host and peripheral manufacturer!
>
>  
>
> The author hopes this material has been helpful in shedding light on the
> issue of FireWire port failures.
>
>  
>
> © 2003 WiebeTech LLC, All Rights Reserved.  FireWire
>
>  
>
>  
>
>  
Thank you to those who made this available
George

Archived from groups: rec.audio.pro (More info?)

In article <20040902074038.15331.00000115@mb-m22.aol.com>,
eganmedia@aol.com (EganMedia) wrote:

> A client brought in a Firewire HD (and his own cable) and fried the firewire
> port on my G4 last summer. Though he bought me a PCI firewire card, he never
> *really* accepted responsibility. I forwarded him the weibetech post. Thanks
> for posting it.
>
I find it astounding they accept having to replacethe 20$cable every
month,granted thier cable most likely would be abused more than mine
that only hooks and unhooks a few times each monh
but still that is a huge problem if the cableing is that suspect and if
you make a mistake about when to buy a new cable you will take out your
computer and possibly the fw device in the process

Archived from groups: rec.audio.pro (More info?)

In article <znr1094132739k@trad>, mrivers@d-and-d.com (Mike Rivers)
wrote:

> In article <g.p.gleason-524324.08220902092004@netnews.worldnet.att.net>
> g.p.gleason@worldnet.att.net writes:
>
> > I find it astounding they accept having to replacethe 20$cable every
> > month,granted thier cable most likely would be abused more than mine
> > that only hooks and unhooks a few times each monh
> > but still that is a huge problem if the cableing is that suspect
>
> The real problem is that that port isn't adequately protected against
> electrical mishaps. The cable and connector just happen to be weak
> points. This is typical of disposable equipment designed for consumer
> use.
>
> In straight audio, it goes back at least as far as the RCA jack. You
> could blow a speaker or something else by 'hot plugging' an RCA cable
> because the ground connection wasn't made first, exposing a sensitive
> input to a nice hum source.
>
I think I'd like to know how to disable the power on the firewire port
and just run my wall wart to my 410

it would seem to me if I can remove the juice from the cable the problem
would really just simply not exist
I doubt data alone could blow out the interface
George

Archived from groups: rec.audio.pro (More info?)

In article <1qffj01a9pi69l0dk66thv87l2fbddhecb@4ax.com>,
Laurence Payne <l@laurenceDELETEpayne.freeserve.co.uk> wrote:

> On Thu, 02 Sep 2004 17:18:40 GMT, George
> <g.p.gleason@worldnet.att.net> wrote:
>
> >>
> > I think I'd like to know how to disable the power on the firewire port
> >and just run my wall wart to my 410
> >
> >it would seem to me if I can remove the juice from the cable the problem
> >would really just simply not exist
> >I doubt data alone could blow out the interface
> >George
>
> Considering the minimal cost of a pci firewire card, are you that
> worried?
>
I am on a G4 titanium laptop
I dont think the cards fit.
George